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Journal articles on the topic 'Phenylalanine Phenylketonuria'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Halil, Kazanasmaz, and Karaca Meryem. "Plasma amino acid levels in a cohort of patients in Turkey with classical phenylketonuria." Asian Biomedicine 14, no. 2 (August 4, 2020): 59–65. http://dx.doi.org/10.1515/abm-2020-0009.

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AbstractBackgroundIn patients with phenylketonuria, the central nervous system is adversely affected by noncompliance with diet. The levels of phenylalanine and many different amino acids (AAs) in the plasma of patients with phenylketonuria can be measured simultaneously.ObjectivesTo measure the blood plasma levels of neurotransmitter AAs in a cohort of patients in Sanliurfa province, Turkey, with phenylketonuria for use as a support parameter for the follow-up of patients.MethodsThe phenylketonurics that we followed (n = 100) were divided into 2 groups according to their compliance with their dietary treatment. Plasma AA analysis results of phenylketonurics were compared with those of healthy children in a control group (n = 50).ResultsIn the diet incompliant group (n = 56), the mean levels of γ-aminobutyric acid (GABA; 0.96 ± 1.07 μmol/L) and glycine (305.1 ± 105.19 μmol/L) were significantly higher than those in the diet compliant group (n = 44; GABA P = 0.005, glycine P < 0.001) and in the control group (GABA and glycine P < 0.001), whereas the mean levels of glutamic acid (39.01 ± 22.94 μmol/L) and asparagine (39.3 ± 16.89 μmol/L) were lower (P < 0.001) in the diet incompliant group. A positive correlation was observed between the levels of phenylalanine and GABA and glycine. A negative relationship was found between the levels of phenylalanine and glutamic acid and asparagine.ConclusionsA relationship exists between the levels of plasma phenylalanine in a cohort of phenylketonurics in Sanliurfa province, Turkey, and the levels of some excitatory and inhibitory AAs. Excitatory and inhibitory AA levels in plasma may be used as support parameters in the follow-up of patients with phenylketonuria.

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2

Barclay, A., and O. Walton. "Phenylketonuria: Implications of Initial Serum Phenylalanine Levels on Cognitive Development." Psychological Reports 63, no. 1 (August 1988): 135–42. http://dx.doi.org/10.2466/pr0.1988.63.1.135.

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This study investigated influences of diagnostic phenylalanines, age at initiation of diet, and dietary control, separately and in combination, on cognitive development for 29 phenylketonuric children (17 boys and 12 girls) who ranged in age from 1 to 1,184 days. Initial serum phenylalanine concentrations and age at initiation of therapy were significantly related to cognitive development, whereas neither dietary and biochemical control relative to blood levels of phenylalanine or for these variables in combination exerted a statistically significant effect on measures of functioning. The interaction between initial serum phenylalanine level and age at onset of diet did reach nearly significant proportions, suggesting that the relation between diagnostic phenylalanines and subsequent cognitive development in the phenylketonuric population warrants further study. Despite an approximately 13-point decrease in IQs between initial (1 yr.) and most recent measurements (3 yr.), all 29 children were functioning in the normal or near-normal intellectual range at the most recent testing.

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3

Clemens, Peter C., Martin H. Schünemann, Alfred Kohlschütter, and Georg F. Hoffman. "Phenylalanine metabolites in phenylketonuria." Journal of Pediatrics 116, no. 4 (April 1990): 665. http://dx.doi.org/10.1016/s0022-3476(05)81624-5.

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4

Murphy, Glynis H., Sally M. Johnson, Allayne Amos, Eleanor Weetch, Rosemary Hoskin, Brian Fitzgerald, Maggie Lilburn, Lesley Robertson, and Philip Lee. "Adults with untreated phenylketonuria: out of sight, out of mind." British Journal of Psychiatry 193, no. 6 (December 2008): 501–2. http://dx.doi.org/10.1192/bjp.bp.107.045021.

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SummarySome people with phenylketonuria who were born before screening began were never treated and are still alive. Here we report that far fewer people with untreated phenylketonuria were detected than are thought to exist (about 2000). The majority of those traced had high support needs, challenging behaviour and other symptoms of phenylketonuria. No significant differences were found between those who had or had not tried the phenylalanine-restricted diet. A randomised controlled trial is required to examine the effect of trying the low-phenylalanine diet for people with untreated phenylketonuria.

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5

Konstantinidis, Georgios, Dobrila Radovanov, and Nada Konstantinidis. "Financial justification of investments into special diet for patients with phenylketonuria." Medical review 63, no. 11-12 (2010): 771–74. http://dx.doi.org/10.2298/mpns1012771k.

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Introduction. Phenylketonuria is a genetic disorder of metabolism of amino acid phenylalanine, which results in the absence of phenylalanine hydroxylase, an enzyme that catalyzes the conversion of phenylalanine into tyrosine. It is an autosomal recessive disorder. Screening for phenylketonuria in Voivodina started in 2003. Screening data are shown in this paper. Treatment of phenylketonuria is based on a strict, life long, low protein diet with the controlled phenylalanine intake. Diet must start early, in the first weeks of life. The aim of the diet is to reduce natural protein intake and to cover protein needs by special phenylalanine free protein products. There is a big variety of formulas found available on the market for treatment of phenylketonuria. All of them are free of phenylalanine and very expensive. Discussion. Till May 2005 there was no refunding for these products in our country. According to the decision made by the Provincial Secretariat for Health, providing all children with protein supplement in their first year of life started at the Institute for Child and Youth Healthcare. In September 2007 the Republic Fund for Health Insurance started to refund protein supplement and low protein products for all children up to the age of 18 years. Conclusion. Besides all technical and organizational difficulties associated with this work, this paper also shows how, by good prevention of phenylketonuria complications, much more money can be saved than it has been invested, even in countries with low amounts of money allocated for this purpose (in absolute figures).

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6

Ben Abdelaziz, Rim, Nizar Tangour, Amel Ben Chehida, Sameh Haj Taieb, Moncef Feki, Hatem Azzouz, and Neji Tebib. "Morning specimen is not representative of metabolic control in Tunisian children with phenylketonuria: a repeated cross-sectional study." Journal of Pediatric Endocrinology and Metabolism 33, no. 8 (August 27, 2020): 1057–64. http://dx.doi.org/10.1515/jpem-2020-0025.

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AbstractObjective and methodsTo evaluate variation of capillary phenylalanine concentrations over the day in patients treated for phenylketonuria and the reliability of the morning sample to assess metabolic control, we conducted a repeated cross-sectional study in 25 Tunisian patients on phenylalanine-low diet. For each patient, we collected nine capillary samples over the day. Phenylalanine was dosed by fluorimetry.ResultsThere was a wide variability of phenylalanine concentrations over the day (p<0.001). Compared to morning sample, phenylalanine concentration was significantly lower before lunch (p=0.038), after lunch (p=0.025), before dinner (p<0.001), after dinner (p=0.035) and at 4:00 a.m. (p=0.011). Compared to the 24 h sampling, the morning sample had a 68% to identify unbalanced patients. 60% of patients, had peak phenylalanine concentration after the morning. Half of the patients with normal morning phenylalanine concentration had low phenylalanine values over 8–20 h. Percentages of high phenylalanine concentrations over the last semester were higher in patients with poor metabolic control over the 24 h (21% ± 43 vs. 0% ± 9%); p=0.043.ConclusionA single morning sample gives an incomplete information on metabolic control in phenylketonuric patients. Using four pre-prandial samples on the day should be considered as alternative in patients with good metabolic control.

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7

VILLEGAS CAMPOS, ELEN, Geanlucas Mendes Monteiro, Elenir Rose Jardim Cury Pontes, and Liane de Rosso Giuliani. "CHARACTERIZATION OF PATIENTS DIAGNOSED WITH PHENYLKETONURIA IN THE NEONATAL TREATMENT REFERENCE SERVICE." International Journal for Innovation Education and Research 7, no. 12 (December 31, 2019): 81–89. http://dx.doi.org/10.31686/ijier.vol7.iss12.2013.

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Phenylketonuria is an inborn error of autosomal recessive genetic metabolism, with partial or total deficiency of the hepatic enzyme phenylalanine hydroxylase, which converts L-phenylalanine into tyrosine, causing accumulation of phenylalanine at brain and serum levels, interfering with brain protein synthesis causing several damages. This study aimed to characterize patients diagnosed with phenylketonuria at the Neonatal Screening Reference Service from 2008 to 2017. Cross-sectional analytical study with a quantitative approach with retrospective data collection from medical records and databases. Data were grouped as baby gender, date of birth, time of birth and neonatal screening examination collection, type of delivery, gestational age and prenatal status, place of origin, phenylketonuria classification and coverage rate of neonatal screening. The sample consisted of 14 patients, where 64% were male, all mothers had prenatal care and the percentage of cesarean delivery prevailed with 57.2%. Of these 85.7% reside in other states of the country and on the classification of the type of phenylketonuria 64.3% have mild phenylketonuria, as for the coverage rate there was a drop in the number of collections in the reference service. This research contributed to characterize the patient diagnosed with phenylketonuria, which allows greater knowledge about the disease carriers, as well as favoring the reduction of irreversible sequels, expenses and morbidity.

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8

Beckhauser, Mayara Thays, Mirella Maccarini Peruchi, Gisele Rozone De Luca, Katia Lin, Sofia Esteves, Laura Vilarinho, and Jaime Lin. "Neuroradiological findings of an adolescent with early treated phenylketonuria: is phenylalanine restriction enough?" Clinics and Practice 1, no. 2 (May 3, 2011): 25. http://dx.doi.org/10.4081/cp.2011.e25.

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Phenylketonuria is caused by mutations in the enzyme phenylalanine hydroxylase gene, that can result in abnormal concentrations of phenylalanine on blood, resulting in metabolites that can cause brain damage. The treatment is based on dietary restriction of phenylalanine, and noncompliance with treatment may result in damage of the brain function. Brain abnormalities can be seen on magnetic resonance imaging of these individuals. Studies indicate that the appearance of abnormalities in white matter reflects high levels of phenylalanine on the blood. This case will show the clinical and neuroradiological aspects of a teenager with constant control of phenylalanine levels. Despite the continuous monitoring and early treatment, the magnetic resonance imaging identified impressive abnormalities in the white matter. This leads us to one question: is the restriction of phenylalanine sufficient to prevent changes in the white matter in patients with phenylketonuria?

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9

Ruiz-Vázquez, P., Y. Bel, A. M. Garcia, M. L. Cabello, J. Dalmau, T. Alós, J. L. Catalá, and J. Ferré. "Measurement of Neopterin and Biopterin in Urine from Phenylketonuria Heterozygotes and Normal Controls." Pteridines 3, no. 3 (September 1991): 177–80. http://dx.doi.org/10.1515/pteridines.1991.3.3.177.

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The effect of an oral load of phenylalanine (100 mg/kg body weight) on the levels of neopterin and biopterin in urine has been determined in 8 heterozygotes for classical phenylketonuria and 25 supposed normal controls. In basal conditions, neopterin and biopterin levels were significantly different between males and females. A significant increase in urinary biopterin was found two hours after the phenylalanine load, both in heterozygotes and in normal homozygotes. This increase was maintained at least until the fourth hour. Neopterin levels did not suffer any change during that period. Comparison of urinary pteridines from normal controls and phenylketonuria carriers showed that there were no significant differences between both groups neither before nor after the phenylalanine load. From these data we concluded that measurement of biopterin and neopterin in urine cannot help in the identification of heterozygotes for phenylketonuria.

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10

Shahid, Samran. "Phylogenetic Analysis of Phenylalanine Hydroxylase Enzyme and Its Future Aspect in Treatment of Phenylalanine Hydroxylase Enzyme Deficiency (Phenylketonuria)." International Journal of Innovative Science and Research Technology 5, no. 7 (July 29, 2020): 569–72. http://dx.doi.org/10.38124/ijisrt20jul519.

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PAH enzyme is one of the most vital enzymes in protein metabolism of the body. The enzyme has been found in various organisms and thus proves it has evolved along with speciation.PAH catalyses hydroxylation of the aromatic side of the phenylalanine to generate Tyrosine (4-hydroxyphenylalanine), one of the 20 standard amino acids that exist. The buildup of excess phenylalanine in the body due to deficiency of PAH causes a condition called Phenylketonuria which causes significant nerve damage. The condition Phenylketonuria is caused due to genetic mutation in PAH gene (Cr.12 )in an individual which can cause PAH enzyme deficiency. The purpose of this analysis was to use the existing Bioinformatics databases to draw relevant similarities of PAH of Homo sapiens and other organism using BLAST , MSA(Multiple Sequence Alignment) and phylogenetic relation while proposing the use of gene therapy using the data derived to cure Phenylketonuria

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11

Peters, Stacy, Deidra Van Gilder, Kyle Dvoracek, and Karly A. Hegge. "Pharmacotherapy Options in the Management of Phenylketonuria." Clinical Medicine Insights: Therapeutics 3 (January 2011): CMT.S6200. http://dx.doi.org/10.4137/cmt.s6200.

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Phenylketonuria (PKU) is an autosomal recessive disorder related to a deficiency in the enzyme phenylalanine hydroxylase (PAH), which converts phenylalanine to tyrosine. As a result, phenylalanine can accumulate in the bloodstream, potentially leading to severe neurologic sequelae. Traditionally, PKU management involves strict dietary phenylalanine restriction, although adherence to this diet is suboptimal, necessitating improved therapeutic options. Sapropterin (Kuvan®) is a synthetic form of tetrahydrobioterin (BH4), a cofactor for PAH, and offers promise for patients with residual enzyme production. In four pivotal phase 2 and 3 trials, as well as several smaller trials, sapropterin has demonstrated significantly improved plasma phenylalanine concentrations in patients with BH4-responsive PKU. Furthermore, data exist to support reduced dependence on a restricted phenylalanine diet. Sapropterin has a favorable safety profile, but further studies are warranted to evaluate its long-term effects. Sapropterin represents a significant advancement in PKU management, and its clinical role may continue to evolve as more data become available and clinicians gain experience with this novel pharmacologic agent.

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12

van Spronsen, Francjan J., and Terry G. J. Derks. "Recombinant phenylalanine ammonia lyase in phenylketonuria." Lancet 384, no. 9937 (July 2014): 6–8. http://dx.doi.org/10.1016/s0140-6736(13)62075-9.

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13

Guldberg, P., K. F. Henriksen, H. C. Lou, and F. Güttler. "Aberrant phenylalanine metabolism in phenylketonuria heterozygotes." Journal of Inherited Metabolic Disease 21, no. 4 (June 1998): 365–72. http://dx.doi.org/10.1023/a:1005398406988.

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14

Murphy, D., I. Saul, and M. Kirby. "Maternal phenylketonuria and phenylalanine restricted diet." Irish Journal of Medical Science 154, no. 2 (February 1985): 66–70. http://dx.doi.org/10.1007/bf02937145.

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15

Porta, Francesco, Alberto Ponzone, and Marco Spada. "Neonatal phenylalanine wash-out in phenylketonuria." Metabolic Brain Disease 35, no. 7 (July 13, 2020): 1225–29. http://dx.doi.org/10.1007/s11011-020-00602-6.

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16

Yan, Shaomin, and Guang Wu. "Connecting Mutant Phenylalanine Hydroxylase With Phenylketonuria." Journal of Clinical Monitoring and Computing 22, no. 5 (September 5, 2008): 333–42. http://dx.doi.org/10.1007/s10877-008-9139-7.

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17

Shedlovsky, A., J. D. McDonald, D. Symula, and W. F. Dove. "Mouse models of human phenylketonuria." Genetics 134, no. 4 (August 1, 1993): 1205–10. http://dx.doi.org/10.1093/genetics/134.4.1205.

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Abstract Phenylketonuria (PKU) results from a deficiency in phenylalanine hydroxylase, the enzyme catalyzing the conversion of phenylalanine (PHE) to tyrosine. Although this inborn error of metabolism was among the first in humans to be understood biochemically and genetically, little is known of the mechanism(s) involved in the pathology of PKU. We have combined mouse germline mutagenesis with screens for hyperphenylalaninemia to isolate three mutants deficient in phenylalanine hydroxylase (PAH) activity and cross-reactive protein. Two of these have reduced PAH mRNA and display characteristics of untreated human PKU patients. A low PHE diet partially reverses these abnormalities. Our success in using high frequency random germline point mutagenesis to obtain appropriate disease models illustrates how such mutagenesis can complement the emergent power of targeted mutagenesis in the mouse. The mutants now can be used as models in studying both maternal PKU and somatic gene therapy.

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18

Shylau, V. V., and H. A. Zhurnia. "DEVELOPMENT OF THE COMPONENT COMPOSITION OF AMINO ACID MIXTURES FOR THE NUTRITION OF PATIENTS WITH PHENYLKETONURIA." Food Industry: Science and Technology 14, no. 1(51) (March 11, 2021): 31–42. http://dx.doi.org/10.47612/2073-4794-2021-14-1(51)-31-42.

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According to the Ministry of Health in the Republic of Belarus in 2019, there were about 500 patients with phenylketonuria (PKU). Phenylketonuria is a hereditary disease associated with a violation of the metabolism of amino acids, in particular phenylalanine (FA). This disease is accompanied by the accumulation of phenylalanine and its toxic products in the tissues, which leads to severe damage to the central nervous system, manifested in the form of impaired mental development. Many years of world experience shows that for the treatment of such patients, a special diet is prescribed using amino acid mixtures that do not contain phenylalanine or contain it in small amounts, as well as low-protein products based on starch, which are necessary to ensure an adequate energy value of the diet. The article presents the stages of development of the component composition of domestic amino acid mixtures for the nutrition of patients with phenylketonuria, taking into account their age characteristics.

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19

Dyshlyuk, Lyubov, Stanislav Sukhikh, Svetlana Noskova, Svetlana Ivanova, Alexander Prosekov, and Olga Babich. "Study of the l-Phenylalanine Ammonia-Lyase Penetration Kinetics and the Efficacy of Phenylalanine Catabolism Correction Using In Vitro Model Systems." Pharmaceutics 13, no. 3 (March 13, 2021): 383. http://dx.doi.org/10.3390/pharmaceutics13030383.

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The kinetics of l-phenylalanine ammonia-lyase (PAL) penetration into the monolayer of liver cells after its release from capsules was studied. The studies showed the absence of the effect of the capsule shell based on plant hydrocolloids on the absorption of l-phenylalanine ammonia-lyase in systems simulating the liver surface. After 120 min of incubation, in all variants of the experiment, from 87.0 to 96.8% of the enzyme penetrates the monolayer of liver cells. The combined analysis of the results concludes that the developed encapsulated form of l-phenylalanine ammonia-lyase is characterized by high efficiency in correcting the disturbed catabolism of phenylalanine in phenylketonuria, which is confirmed by the results of experiments carried out on in vitro model systems. PAL is approved for the treatment of adult patients with phenylketonuria. The encapsulated l-phenylalanine ammonia-lyase form can find therapeutic application in the phenylketonuria treatment after additional in vitro and in vivo studies, in particular, the study of preparation safety indicators. Furthermore, it demonstrated high efficacy in tumor regression and the treatment of tyrosine-related metabolic disorders such as tyrosinemia. Several therapeutically valuable metabolites biosynthesized by PAL via its catalytic action are included in food supplements, antimicrobial peptides, drugs, amino acids, and their derivatives. PAL, with improved pharmacodynamic and pharmacokinetic properties, is a highly effective medical drug.

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20

Yakubovskii, Grigorii I., Olga B. Serebriakova, Alina G. Yakubovskaya, Nadezhda V. Ruban, and Angelina A. Lyakhovets. "Clinical and Genetic Characteristics of Phenylketonuria in Ryazan Region." I.P. Pavlov Russian Medical Biological Herald 29, no. 1 (March 15, 2021): 5–12. http://dx.doi.org/10.23888/pavlovj20212915-12.

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Aim. This investigation seeks to determine the incidence of phenylketonuria in the Ryazan region, assess the spectrum of mutations in the PAH gene (phenylalanine hydroxylase), investigate the interrelationship between the diseases clinical course, the phenylalanine blood level, and the patients genotype. Materials and Methods. The incidence of phenylketonuria was studied based on the data of massive neonatal screening for the period from 2000 to 2019. Molecular genetic examination of mutations was conducted in 39 patients using the allele-specific multiplex ligation method. The interrelationship between the phenylalanine blood level on the fifth day of life and retest, the diseases clinical course, and the patients genotype was assessed according to the medical record data of 33 patients under dispensary observation in a medico-genetic clinic. The patients were divided into two groups. The first group (n=21) had two severe mutations (residual activity of phenylalanine hydroxylase 10%). The second group (n=12) had one severe and one mild mutation (the residual activity of the enzyme 10%). Results. The incidence of phenylketonuria in the Ryazan region was one in 5054 newborns, exceeding the Russian Federations average parameters. Eighteen mutations were discovered in the PAH gene. The most frequent was the R408W mutation (56.4% alleles). The second most frequent mutations were the IVS10-11GA (6.4%) and P281L (5.1%). The R158Q and Y418C mutations occurred with a frequency of 4.1% and Е280К mutation of 2.7%. All the rest of the mutations occurred as single cases. Investigation of the interrelationship between the phenylalanine blood level, the diseases clinical course, and the patients genotype revealed a reliably higher content of amino acid in the first group on retest (32.11.7 mg/% vs. 17.71.5 mg/% in the second group, р0.001) and predomination of more severe forms of phenylketonuria (90.5% vs. 41.7%, respectively, р0.001). Disorders in neuropsychic and speech development were present in 28.6% of patients in the first group but were absent in the second group. Conclusion. By conducting the study, the incidence of phenylketonuria was determined in the Ryazan region. The spectrum of mutations in the PAH gene was defined. The interrelationship between the diseases clinical portrait, the phenylalanine blood level, and the patients PAH genotype was revealed.

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21

Walkowiak, Marek, Łukasz Kałużny, Renata Mozrzymas, Małgorzata Jamka, Bożena Mikołuć, Joanna Jagłowska, Ewa Starostecka, Roza Nurgaliyeva, Jarosław Walkowiak, and Aleksandra Lisowska. "Helicobacter pylori Infection in Children with Phenylketonuria Does Not Depend on Metabolic Control and Is Not More Frequent Than in Healthy Subjects—A Cross-Sectional Study." Children 8, no. 8 (August 19, 2021): 713. http://dx.doi.org/10.3390/children8080713.

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In a small preliminary study, phenylketonuria and poor metabolic control were suggested as risk factors for Helicobacter pylori infection in children as detected with an antigen stool test. We aimed to determine Helicobacter pylori prevalence in an adequately sized group of individuals with phenylketonuria and healthy subjects using the standard gold test (urea breath test). Further, we correlated Helicobacter pylori infection with metabolic control. The study comprised 103 individuals with phenylketonuria and 103 healthy subjects on whom a 13C urea breath test was performed. Blood phenylalanine levels in the preceding year were analysed. The infection rate did not differ between individuals with phenylketonuria and healthy subjects (10.7% vs 15.5%; p = 0.41). The frequency of testing and phenylalanine concentrations of Helicobacter pylori-positive and Helicobacter pylori-negative patients with phenylketonuria did not differ (p = 0.92 and p = 0.54, respectively). No associations were detected for body mass index or metabolic control. Forward stepwise regression models revealed that age (p = 0.0009–0.0016) was the only independent correlate of Helicobacter pylori infection with a relatively low fraction of the variability of the condition being explained (adjR2 = 0.0721–0.0754; model p = 0.020–0.023). In conclusion, Helicobacter pylori infection in phenylketonuria is not more frequent than in the general population. Moreover, it does not depend on metabolic control.

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Ledley, F. D., H. E. Grenett, B. S. Dunbar, and S. L. C. Woo. "Mouse phenylalanine hydroxylase. Homology and divergence from human phenylalanine hydroxylase." Biochemical Journal 267, no. 2 (April 15, 1990): 399–405. http://dx.doi.org/10.1042/bj2670399.

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The laboratory mouse represents an important model for the study of phenylalanine metabolism and the pathochemistry of phenylketonuria, yet mouse phenylalanine hydroxylase (PAH) has not been extensively studied. We report the cloning and sequencing of a mouse PAH cDNA, the expression of enzymic activity from the mouse PAH cDNA clone and the identification of mouse PAH and human PAH by two-dimensional PAGE of liver samples. These data confirm the expected homology of mouse PAH and human PAH and suggest differences in the primary sequence and the phosphorylation state of the two enzymes.

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23

Bókay, János, Erika Kiss, Erika Simon, and László Szőnyi. "Maternal phenylketonuria." Orvosi Hetilap 154, no. 18 (May 2013): 683–87. http://dx.doi.org/10.1556/oh.2013.29595.

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Elevated maternal phenylalanine levels during pregnancy are teratogenic, and may result in embryo-foetopathy, which could lead to stillbirth, significant psychomotor handicaps and birth defects. This foetal damage is known as maternal phenylketonuria. Women at the childbearing age with all forms of phenylketonuria, including mild variants such as hyperphenylalaninaemia, should receive detailed counselling regarding their risks for adverse foetal effects, optimally before contemplating pregnancy. The most assured way to prevent maternal phenylketonuria is to maintain the maternal phenylalnine levels within the optimal range already before conception and throughout the whole pregnancy. Authors review the comprehensive programme for prevention of maternal phenylketonuria at the Metabolic Center of Budapest, they survey the practical approach of the continuous maternal metabolic control and delineate the outcome of pregnancies of mothers with phenylketonuria from the introduction of newborn screening until recently. Orv. Hetil., 2013, 154, 683–687.

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24

van Spronsen, Francjan J., Margreet van Rijn, Jolita Bekhof, Richard Koch, and Peter GA Smit. "Phenylketonuria: tyrosine supplementation in phenylalanine-restricted diets." American Journal of Clinical Nutrition 73, no. 2 (February 1, 2001): 153–57. http://dx.doi.org/10.1093/ajcn/73.2.153.

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van Spronsen, F. J., P. G. A. Smit, and R. Koch. "Phenylketonuria: Tyrosine beyond the phenylalanine-restricted diet." Journal of Inherited Metabolic Disease 24, no. 1 (February 2001): 1–4. http://dx.doi.org/10.1023/a:1005689232358.

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26

Ledley, Fred D., Anthony G. DiLella, and Savio L. C. Woo. "Molecular biology of phenylalanine hydroxylase and phenylketonuria." Trends in Genetics 1 (January 1985): 309–13. http://dx.doi.org/10.1016/0168-9525(85)90121-0.

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27

Schlegel, Gudrun, Ralf Scholz, Kurt Ullrich, René Santer, and Gabriele M. Rune. "Phenylketonuria: Direct and indirect effects of phenylalanine." Experimental Neurology 281 (July 2016): 28–36. http://dx.doi.org/10.1016/j.expneurol.2016.04.013.

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28

Clemens, P. C., J. G. Burmester, B. H. Prankel, G. Wiegand, A. P. Wulke, and C. Plettner. "Phenylalanine and other amino acids in phenylketonuria." Journal of Inherited Metabolic Disease 16, no. 6 (1993): 1045–46. http://dx.doi.org/10.1007/bf00711525.

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de Groot, Martijn J., Paul E. Sijens, Dirk-Jan Reijngoud, Anne M. Paans, and Francjan J. van Spronsen. "Phenylketonuria: Brain Phenylalanine Concentrations Relate Inversely to Cerebral Protein Synthesis." Journal of Cerebral Blood Flow & Metabolism 35, no. 2 (October 29, 2014): 200–205. http://dx.doi.org/10.1038/jcbfm.2014.183.

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In phenylketonuria, elevated plasma phenylalanine concentrations may disturb blood-to-brain large neutral amino acid (LNAA) transport and cerebral protein synthesis (CPS). We investigated the associations between these processes, using data obtained by positron emission tomography with l-[1-11C]-tyrosine (11C-Tyr) as a tracer. Blood-to-brain transport of non-Phe LNAAs was modeled by the rate constant for 11C-Tyr transport from arterial plasma to brain tissue (K1), while CPS was modeled by the rate constant for 11C-Tyr incorporation into cerebral protein (k3). Brain phenylalanine concentrations were measured by magnetic resonance spectroscopy in three volumes of interest (VOIs): supraventricular brain tissue (VOI 1), ventricular brain tissue (VOI 2), and fluid-containing ventricular voxels (VOI 3). The associations between k3 and each predictor variable were analyzed by multiple linear regression. The rate constant k3 was inversely associated with brain phenylalanine concentrations in VOIs 2 and 3 (adjusted R2=0.826, F=19.936, P=0.021). Since brain phenylalanine concentrations in these VOIs highly correlated with each other, the specific associations of each predictor with k3 could not be determined. The associations between k3 and plasma phenylalanine concentration, K1, and brain phenylalanine concentrations in VOI 1 were nonsignificant. In conclusion, our study shows an inverse association between k3 and increased brain phenylalanine concentrations.

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Hegge, Karly A., Kristin K. Horning, Gregory J. Peitz, and Kassy Hegge. "Sapropterin: A New Therapeutic Agent for Phenylketonuria." Annals of Pharmacotherapy 43, no. 9 (August 4, 2009): 1466–73. http://dx.doi.org/10.1345/aph.1m050.

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Objective: To summarize the role of pharmacotherapy in the management of phenylketonuria (PKU) and to review the pharmacology, pharmacokinetics, pharmacodynamics, efficacy data, and safety profile of sapropterin for this indication. Data Sources: A literature search was conducted using MEDLINE (1966–May 2009), International Pharmaceutical Abstracts (1970–May 2009), and Cochrane database (2008) for the following key words: sapropterin, tetrahydrobiopterin, phenylketonurias, and phenylalanine. Study Selection and Data Extraction: English-language studies involving humans examining the role of tetrahydrobiopterin (BH4) in the management of PKU were reviewed to evaluate the pharmacology, pharmacokinetics, pharmacodynamics, efficacy data, and safety profile for sapropterin. All Phase 2 and 3 randomized controlled trials assessing the safety and efficacy of sapropterin were included in this literature evaluation. Data Synthesis: Sapropterin represents the only Food and Drug Administration–approved medication for BH4-responsive PKU, marking an important advance in the treatment of this condition. Among individuals with hyperphenylalaninemia and some residual phenylalanine hydroxylase function, sapropterin can enhance activity of this enzyme to decrease serum phenylalanine concentrations. Sapropterin has been compared with placebo in one Phase 2 and one Phase 3 clinical trial, demonstrating significantly better response rates. Based on available studies, this agent appears to be safe and well tolerated, with adverse event rates similar to those of placebo. However, additional studies are warranted to assess the long-term safety and efficacy of sapropterin therapy. Conclusions: Sapropterin offers a promising therapeutic option for select individuals with BH4-responsive PKU, although long-term data are limited evaluating its safety and efficacy in traditional clinical practice settings. When considering sapropterin therapy, clinicians must consider factors such as cost and patient adherence to drug therapy and/or diet.

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Zekanowsk, C., B. Perez, L. R. Desviat, W. Wiszniewski, and M. Ugarte. "In vitro expression analysis of R68G and R68S mutations in phenylalanine hydroxylase gene." Acta Biochimica Polonica 47, no. 2 (June 30, 2000): 365–69. http://dx.doi.org/10.18388/abp.2000_4016.

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Phenylketonuria (PKU), an autosomal recessive disorder caused be a deficiency of hepatic phenylalanine hydroxylase (PAH), is clinically very heterogeneous. At the molecular level, more than 400 mutations in the PAH gene are known to date, which in different genotype combinations could account for biochemical and clinical variability of symptoms. In vitro expression studies on R68G and R68S mutations causing mild phenylketonuria are presented.

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Messina, M. A., C. Meli, S. Conoci, and S. Petralia. "A facile method for urinary phenylalanine measurement on paper-based lab-on-chip for PKU therapy monitoring." Analyst 142, no. 24 (2017): 4629–32. http://dx.doi.org/10.1039/c7an01115f.

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Kavecan, Ivana, Jadranka Jovanovic, Boris Privrodski, Milan Obrenovic, and Tatjana Redzek-Mudrinic. "Fourteen years of newborn screening for phenylketonuria in Vojvodina." Medical review 70, no. 11-12 (2017): 411–15. http://dx.doi.org/10.2298/mpns1712411k.

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Introduction. Phenylketonuria is an inborn disorder of metabolism, a rare, hereditary disease caused by deficiency of phenylalanine hydroxylase enzyme necessary for conversion of phenylalanine into tyrosine. The aim of this study is to determine the incidence of hyperphenylalaninemia and classical phenylketonuria in population of the Autonomous Province of Vojvodina. Material and Methods. We performed retrospective analysis at Medical Genetics Service, the Institute for Youth and Health Care of Vojvodina and examined the clinical material of the previous fourteen years, during the interval from 2003-2016. The analysis of the obtained results was carried out using descriptive statistics. Results. During fourteen years, from 01.01.2003 to 31.12.2016, 27 newborns with hyperphenylalaninemia were detected, and the incidence of hyperphenylalaninemia in the Autonomous Province of Vojvodina was 1: 9.525. Classical phenylketonuria was detected in 15 persons during indicated period, and the incidence was 1:17.143. Conclusion. Phenylketonuria is a hereditary disease whose adverse effects can be avoided, if it is recognized in time, and if recommended treatment measures are adequately applied, thereby improving the quality of life of persons affected by the disease as well as the whole family, that is facilitated by the introduction and implementation of neonatal screening.

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Shiva, Siamak, and Yalda Jabbari Moghaddam. "Hearing in Children with Phenylketonuria." Advances in Bioscience and Clinical Medicine 6, no. 3 (July 31, 2018): 16. http://dx.doi.org/10.7575/aiac.abcmed.v.6n.3p.16.

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Background: Phenylalanine is an essential Acid Amine participates in protein synthesis by tyrosine. High levels of phenylalanine in the body lead to the production of large quantities of phenyl ketone, which is excreted through urine and that is why it called as Phenylketonuria. A defect of IQ and attention, visual ability and speech processing in this patient. the aim of this study was hearing threshold evaluation of this patient. Method: In a cross-sectional, descriptive study auditory brain stem responses and otoacoustic emission of patients from 1 to13 years and control group age range of 1 to 14 years evaluated. Results: In 31 patients (62%) delay in ABR waves were outside of the normal range but the overall mean of all waves had in the normal range and the average interval of waves in patients with delay in treatment delay was more than patients group with early treatment. Conclusion: delayed-treatment was faced with more delays in the intervals between ABR waves, although statistically was not significant.

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Al-Imam, Ahmed. "The digital epidemiology of phenylketonuria, aka folling’s disease: retrospective analysis and geographic mapping via google trends." Asian Journal of Medical Sciences 9, no. 6 (October 29, 2018): 93–99. http://dx.doi.org/10.3126/ajms.v9i6.20497.

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Background: Phenylketonuria, commonly known as PKU, is an inherited disorder in which there is an abnormally elevated blood level of the amino acid phenylalanine leading to several pathologies affecting multiple organs including the central nervous system and resulting in debilitating intellectual disability and other neuropsychiatric disorders. Phenylalanine is a building block of several critical proteins within the biological systems.Aims and Objective: To assess the digital epidemiology and geographic mapping of Phenylketonuria.Materials and Methods: This study is a retrospective analytic (2013‑2017) of a very large database existing on the surface web known as Google Trends. it aims to extrapolate a statistical inference concerning the digital epidemiology and the geographic mapping of phenylketonuria. The trends database will be explored via thematic keywords specific to the condition of phenylketonuria including “Phenylketonuria [PKU]”, “Phenylalanine”, “Inborn errors of metabolism”, “Tetrahydrobiopterin”, and “Chromosome 12 (human)”.Results: The digital epidemiology is densely clustered in countries from the developed world, eastern Europe, and Latin America. Surface web users from China appears to possess the highest interest in phenylketonuria. The contribution of the Middle Eastern and Arabic countries to the geographic mapping did not exceed 10.51% at its best. Significant changes existed for year-to-year variations of trends. Statistical outliers were also found, the strongest of which was observed during April 2016 for which there’s no plausible explanation.Conclusion: Trends databases operating on the surface web represent potent tools of big data that can be exploited to assess the digital epidemiology and geographic mapping of countless phenomenon including rare genetic diseases and inborn errors of metabolism. There are also enormous potentials for real-time and predictive analytics of these databases when investing the application of automation in data collection and principles of machine learning.Asian Journal of Medical Sciences Vol.9(6) 2018 93-99

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Henderson, M. J., L. Shapiro, and C. McCowan. "Galactosemia detection from phenylketonuria screening." Clinical Chemistry 34, no. 1 (January 1, 1988): 188–89. http://dx.doi.org/10.1093/clinchem/34.1.188.

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Abstract We describe a case of classical galactosemia in which the diagnosis was first suggested by the finding of a moderately increased blood-spot phenylalanine concentration. The child was clinically unaffected at six days when the initial sample was collected. Prompt institution of dietary management averted a serious metabolic crisis.

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MacDonald, Anita, Kirsten Ahring, Katharina Dokoupil, Hulya Gokmen-Ozel, Anna Maria Lammardo, Kristina Motzfeldt, Martine Robert, Júlio César Rocha, Margreet van Rijn, and Amaya Bélanger-Quintana. "Adjusting diet with sapropterin in phenylketonuria: what factors should be considered?" British Journal of Nutrition 106, no. 2 (April 5, 2011): 175–82. http://dx.doi.org/10.1017/s0007114511000298.

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The usual treatment for phenylketonuria (PKU) is a phenylalanine-restricted diet. Following this diet is challenging, and long-term adherence (and hence metabolic control) is commonly poor. Patients with PKU (usually, but not exclusively, with a relatively mild form of the disorder) who are responsive to treatment with pharmacological doses of tetrahydrobiopterin (BH4) have either lower concentrations of blood phenylalanine or improved dietary phenylalanine tolerance. The availability of a registered formulation of BH4 (sapropterin dihydrochloride, Kuvan®) has raised many practical issues and new questions in the dietary management of these patients. Initially, patients and carers must understand clearly the likely benefits (and limitations) of sapropterin therapy. A minority of patients who respond to sapropterin are able to discontinue the phenylalanine-restricted diet completely, while others are able to relax the diet to some extent. Care is required when altering the phenylalanine-restricted diet, as this may have unintended nutritional consequences and must be undertaken with caution. New clinical protocols are required for managing any dietary change while maintaining control of blood phenylalanine, ensuring adequate nutrition and preventing nutritional deficiencies, overweight or obesity. An accurate initial evaluation of pre-sapropterin phenylalanine tolerance is essential, and the desired outcome from treatment with sapropterin (e.g. reduction in blood phenylalanine or relaxation in diet) must also be understood by the patient and carers from the outset. Continuing education and support will be required thereafter, with further adjustment of diet and sapropterin dosage as a young patient grows.

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Thiessen, Gregory, Robert Robinson, Kim De Los Reyes, Raymond J. Monnat, and Elain Fu. "Conversion of a laboratory-based test for phenylalanine detection to a simple paper-based format and implications for PKU screening in low-resource settings." Analyst 140, no. 2 (2015): 609–15. http://dx.doi.org/10.1039/c4an01627k.

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Barta, András Gellért, Csaba Sumánszki, and Péter Reismann. "Csontanyagcsere felnőtt phenylketonuriás pácienseknél – hazai adatok." Orvosi Hetilap 158, no. 47 (November 2017): 1868–72. http://dx.doi.org/10.1556/650.2017.30889.

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Abstract: Introduction: Patients with phenylketonuria have lower bone mineral density compared to healthy people, however, the ethiology of these alterations is not clear. Hungarian data were missing in this topic. Aim: The main aim of our study was to survey the correlation between metabolic control and change of bone mineral density in early treated Hungarian adult patients with phenylketonuria. Method: In this monocentric study bone mineral density of 59 adult PKU patients have been repeatedly measured in a 4-year interval using dual-energy X-ray absorptiometry. Two subgroups have been established based on average blood phenylalanine levels. The correlation between the change in bone mineral density and average phenylalanine, tyrosine concentrations have been determined while initial bone mineral density and change have also been examined in the subgroups. Results: Mean phenylalanine concentration was 614 (182–1222) micromol/L, whereas mean tyrosine concentration was 49 (24–99) micromol/L and the calculated ratio was 16 (4,5–35). Three patients have had severely decreased bone mineral density in either localisation while 22 have had mild decrease. Low bone mineral density compared to cronological age has been found by 9 patient. The mean change was +0.0380 (–0.1550–0.7800) g/cm2 in femur, and +0.0120 (–0.57300–0.3130) g/cm2 in the lumbar spine. There was a correlation in the change in Z-score neither with mean phenylalanine nor with tyrosine concentration. Conclusions: Bone mineral density was not changed and hardly influenced by the metabolic control in early-treated young adult phenylketonuria patients in a few years interval. Orv Hetil. 2017; 158(47): 1868–1872.

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Koch, Richard, Rex Moats, Flemming Guttler, Per Guldberg, and Marvin Nelson. "Blood–Brain Phenylalanine Relationships in Persons With Phenylketonuria." Pediatrics 106, no. 5 (November 1, 2000): 1093–96. http://dx.doi.org/10.1542/peds.106.5.1093.

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41

Hoeksma, Marieke, Dirk-Jan Reijngoud, Jan Pruim, Harold W. de Valk, Anne M. J. Paans, and Francjan J. van Spronsen. "Phenylketonuria: High plasma phenylalanine decreases cerebral protein synthesis." Molecular Genetics and Metabolism 96, no. 4 (April 2009): 177–82. http://dx.doi.org/10.1016/j.ymgme.2008.12.019.

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Okano, Yoshiyuki, and Hironori Nagasaka. "Optimal serum phenylalanine for adult patients with phenylketonuria." Molecular Genetics and Metabolism 110, no. 4 (December 2013): 424–30. http://dx.doi.org/10.1016/j.ymgme.2013.09.007.

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43

Dooley, Kent C. "Enzymatic method for phenylketonuria screening using phenylalanine dehydrogenase." Clinical Biochemistry 25, no. 4 (August 1992): 271–75. http://dx.doi.org/10.1016/0009-9120(92)80032-c.

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Carlson, Harold E., David B. Hyman, Cindy Bauman, and Richard Koch. "Prolactin responses to phenylalanine and tyrosine in phenylketonuria." Metabolism 41, no. 5 (May 1992): 518–21. http://dx.doi.org/10.1016/0026-0495(92)90211-r.

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45

Dekel, B. Z., Y. Cohen, and M. Feldman. "Study of Phenylalanine NIR Spectra for Phenylketonuria Determination." Journal of Applied Spectroscopy 87, no. 6 (January 2021): 1179–84. http://dx.doi.org/10.1007/s10812-021-01127-1.

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46

Daly, A., S. Evans, S. Chahal, S. Santra, and A. MacDonald. "Glycomacropeptide in children with phenylketonuria: does its phenylalanine content affect blood phenylalanine control?" Journal of Human Nutrition and Dietetics 30, no. 4 (January 22, 2017): 515–23. http://dx.doi.org/10.1111/jhn.12438.

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47

Spada, M., I. Dianzani, G. Bonetti, A. Biondi, L. Leone, and A. Ponzone. "Phenylalanine and tyrosine metabolism in phenylketonuria heterozygotes: Influence of different phenylalanine hydroxylase mutations." Journal of Inherited Metabolic Disease 21, no. 3 (June 1998): 236–39. http://dx.doi.org/10.1023/a:1005355802928.

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48

Mocanu, Cosmin Stefan, Ana-Simona Bocec, Vasile Robert Gradinaru, and Dana-Teodora Anton-Paduraru. "A Biochemical Method for Tyrosine Determination in Phenylketonuria Using a Colorimetric Enzymatic Approach." Revista de Chimie 71, no. 9 (September 5, 2020): 285–94. http://dx.doi.org/10.37358/rc.20.9.8339.

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Phenylketonuria is a serious genetic disease caused by a deficiency of phenylalanine metabolism, an essential amino acid found in daily nutrition. This disorder is caused by the lack of a specific enzyme called phenylalanine hydroxylase which mediates the conversion of phenylalanine to tyrosine). Thus, after ingestion of phenyl alanine-rich proteins, the amino acid concentration increases considerably in the blood due to proteolysis. Genetic deffects of enzymes responsible for phenylalanine metabolic conversion were intensively studied. Among them the defect of gene encoding phenylalanine hydroxylase has a higher notoriety. This genetic defect is translated in an inactive enzyme constructs that impair the aminoacid hydroxylation. This physiological stage is also called hyperphenylalaninemia where slightly high levels of phenylalanine are noticed in the blood or urine. Consequently, the amino acid is converted to phenylpyruvic acid by transamination, the later displaying a particularly toxic effect against brain tissues. The aim of this study was to quantify tyrosine in the blood of patients suffering of phenylketonuria by an alternative enzymatic method. The tyrosinase used in this assay was extracted from commercial mushrooms (Agaricus bisporus) following the Haghbeen protocol with some modifications. Two chromatographic steps (molecular exclusion chromatography and ionic exchange chromatography) were used during the enzyme purification process. High purity samples were concentrated using ultrafiltration. The tyrosinase was screened by a classical enzymatic microplate assay having DOPA as a substrate. Finally the pure enzyme was used in order to quantify tyrosine from different standard solutions. The level of tyrosine from deproteinized serum samples was determined using a similar enzymatic strategy.

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Andreacchio, A., G. P. Molinari, and P. L. Oreste. "Two Cases of Ochronotic Arthropathy." HIP International 2, no. 3-4 (July 1992): 88–93. http://dx.doi.org/10.1177/112070009200203-404.

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Phenylketonuria is a congenital inborn error of metabolism of phenylalanine hydroxylase. Characteristic arthrosis called ochronotic arthropathy is localized at main joints. The Authors present two cases of ochronotic arthropathy. Clinical and radiological features are described.

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50

Vilaseca, M. A., C. Farré, and F. Ramón. "Phenylalanine determined in plasma with use of phenylalanine dehydrogenase and a centrifugal analyzer." Clinical Chemistry 39, no. 1 (January 1, 1993): 129–31. http://dx.doi.org/10.1093/clinchem/39.1.129.

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Abstract Quantitative determination of plasma phenylalanine (Phe) is essential for the diagnosis of phenylketonuria (PKU) and the control of dietary therapy of PKU patients. We have adapted a spectrophotometric method (Clin Chim Acta 1991;201:95-8) based on phenylalanine dehydrogenase (EC 1.4.1.-) for rapid and accurate determinations of Phe with the Cobas Fara II centrifugal analyzer. The method is based on the NAD(H)-dependent reductive deamination of Phe with large amounts of phenylalanine dehydrogenase, which catalyzes the formation of phenylpyruvate at pH 10.8. Combining the specificity of the phenylalanine dehydrogenase with the precision, accuracy, and considerable time-saving of an automated system is useful for monitoring PKU patients in a children's hospital.

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