Genotype-phenotype correlations and BH4 estimated responsiveness in patients with phenylketonuria from Rio de Janeiro, Southeast Brazil. 2019

Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
Agência Nacional de Saúde Suplementar, Gerência de Monitoramento Assistencial, Rio de Janeiro, Brazil.

Genetic heterogeneity and compound heterozygosis give rise to a continuous spectrum of phenylalanine hydroxylase deficiency and metabolic phenotypes in phenylketonuria (PKU). The most used parameters for evaluating phenotype in PKU are pretreatment phenylalanine (Phe) levels, tolerance for dietary Phe, and Phe overloading test. Phenotype can vary from a "classic" (severe) form to mild hyperphenylalaninemia, which does not require dietary treatment. A subset of patients is responsive to treatment by the cofactor tetrahydrobiopterin (BH4 ). Genotypes of PKU patients from Rio de Janeiro, Brazil, were compared to predicted and observed phenotypes. Genotype-based estimations of responsiveness to BH4 were also conducted. Phenotype was defined by pretreatment Phe levels. A standard prediction system based on arbitrary assigned values was employed to measure genotype-phenotype concordance. Patients were also estimated as BH4 -responders according to the responsiveness previously reported for their mutations and genotypes. A 48.3% concordance rate between genotype-predicted and observed phenotypes was found. When the predicted phenotypes included those reported at the BIOPKU database, the concordance rate reached 77%. A total of 18 genotypes from 30 patients (29.4%) were estimated as of potential or probable BH4 responsiveness. Inconsistencies were observed in genotypic combinations including the common "moderate" mutations p.R261Q, p.V388M, and p.I65T and the mild mutations p.L48S, p.R68S, and p.L249F. The high discordance rate between genotype-predicted and observed metabolic phenotypes in this study seems to be due partially to the high frequency of the so-called "moderate" common mutations, p.R261Q, p.V388M, and p.I65T, which are reported to be associated to erratic or more severe than expected metabolic phenotypes. Although our results of BH4 estimated responsiveness must be regarded as tentative, it should be emphasized that genotyping and genotype-phenotype association studies are important in selecting patients to be offered a BH4 overload test, especially in low-resource settings like Brazil.

UI MeSH Term Description Entries
D010641 Phenotype The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment. Phenotypes
D010651 Phenylalanine Hydroxylase An enzyme of the oxidoreductase class that catalyzes the formation of L-TYROSINE, dihydrobiopterin, and water from L-PHENYLALANINE, tetrahydrobiopterin, and oxygen. Deficiency of this enzyme may cause PHENYLKETONURIAS and PHENYLKETONURIA, MATERNAL. EC 1.14.16.1. Phenylalanine 4-Hydroxylase,Phenylalanine 4-Monooxygenase,4-Hydroxylase, Phenylalanine,4-Monooxygenase, Phenylalanine,Hydroxylase, Phenylalanine,Phenylalanine 4 Hydroxylase,Phenylalanine 4 Monooxygenase
D010661 Phenylketonurias A group of autosomal recessive disorders marked by a deficiency of the hepatic enzyme PHENYLALANINE HYDROXYLASE or less frequently by reduced activity of DIHYDROPTERIDINE REDUCTASE (i.e., atypical phenylketonuria). Classical phenylketonuria is caused by a severe deficiency of phenylalanine hydroxylase and presents in infancy with developmental delay; SEIZURES; skin HYPOPIGMENTATION; ECZEMA; and demyelination in the central nervous system. (From Adams et al., Principles of Neurology, 6th ed, p952). Biopterin Deficiency,Dihydropteridine Reductase Deficiency Disease,Hyperphenylalaninemia, Non-Phenylketonuric,Phenylalanine Hydroxylase Deficiency Disease,BH4 Deficiency,DHPR Deficiency,Deficiency Disease, Dihydropteridine Reductase,Deficiency Disease, Phenylalanine Hydroxylase,Deficiency Disease, Phenylalanine Hydroxylase, Severe,Dihydropteridine Reductase Deficiency,Folling Disease,Folling's Disease,HPABH4C,Hyperphenylalaninaemia,Hyperphenylalaninemia Caused by a Defect in Biopterin Metabolism,Hyperphenylalaninemia, BH4-Deficient, C,Hyperphenylalaninemia, Tetrahydrobiopterin-Deficient, Due To DHPR Deficiency,Non-Phenylketonuric Hyperphenylalaninemia,Oligophrenia Phenylpyruvica,PAH Deficiency,PKU, Atypical,Phenylalanine Hydroxylase Deficiency,Phenylalanine Hydroxylase Deficiency Disease, Severe,Phenylketonuria,Phenylketonuria I,Phenylketonuria II,Phenylketonuria Type 2,Phenylketonuria, Atypical,Phenylketonuria, Classical,QDPR Deficiency,Quinoid Dihydropteridine Reductase Deficiency,Tetrahydrobiopterin Deficiency,Atypical PKU,Atypical Phenylketonuria,Biopterin Deficiencies,Classical Phenylketonuria,Deficiency, BH4,Deficiency, Biopterin,Deficiency, DHPR,Deficiency, Dihydropteridine Reductase,Deficiency, PAH,Deficiency, Phenylalanine Hydroxylase,Deficiency, QDPR,Deficiency, Tetrahydrobiopterin,Disease, Folling,Disease, Folling's,Hyperphenylalaninemia, Non Phenylketonuric,Non Phenylketonuric Hyperphenylalaninemia,Non-Phenylketonuric Hyperphenylalaninemias
D001938 Brazil A country located on the eastern coast of South America, located between Colombia and Peru, that borders the Atlantic Ocean. It is bordered on the north by Venezuela, Guyana, Suriname, and French Guiana, on the south by Uruguay, and on the west by Argentina. The capital is Brasilia.
D005838 Genotype The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS. Genogroup,Genogroups,Genotypes
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000071184 Pharmacogenomic Variants Naturally occurring genetic variations associated with drug response (e.g., dosage, extent and rate of metabolic processes). While these variants are not markers for GENETIC PREDISPOSITION TO DISEASE they influence PHARMACOKINETICS and pharmacodynamics and often occur on genes encoding drug metabolism enzymes and transporters (e.g., ANGIOTENSIN CONVERTING ENZYME; CYTOCHROME P-450 CYP2D6). Pharmacogenetic Variants,Pharmacokinetic Genetic Variants,Genetic Variant, Pharmacokinetic,Genetic Variants, Pharmacokinetic,Pharmacogenetic Variant,Pharmacogenomic Variant,Pharmacokinetic Genetic Variant,Variant, Pharmacogenetic,Variant, Pharmacogenomic,Variants, Pharmacogenetic,Variants, Pharmacogenomic
D001708 Biopterins Pterin derivatives based on 2-amino-6-(1,2-dihydroxypropyl)-4(1H)-pteridinone. Biopterins are natural products that have been considered as growth factors for some insects. Biopterins are cofactors for the AROMATIC AMINO ACID hydroxylases and NITRIC OXIDE SYNTHASE. Deficiencies in BIOPTERINS metabolism (e.g., lowered TETRAHYDROBIOPTERIN) are associated with neurological deterioration (e.g., HYPERPHENYLALANINAEMIA). 2-Amino-6-((1S,2R)-1,2-dihydroxypropyl)-4(1H)-pteridinone,2-Amino-6-((1S,2S)-1,2-dihydroxypropyl)-4(1H)-pteridinone,2-Amino-6-(1,2-dihydroxypropyl)-4(8H)-pteridinone,2-amino-6-((1R,2R)-1,2-dihydroxypropyl)-4(3H)-pteridinone,4(1H)-Pteridinone, 2-amino-6-(1,2-dihydroxypropyl)-, (S-(R*,S*))-,6-Biopterin,Biopterin,D-threo-Biopterin,L-Biopterin,L-erythro-Biopterin,L-threo-Biopterin,2-Amino-6-(1,2-dihydroxypropyl)-4(1H)-pteridinone,Dictyopterin,Orinapterin,6 Biopterin,D threo Biopterin,L Biopterin,L erythro Biopterin,L threo Biopterin

Related Publications

Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
August 2016, Journal of human genetics,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
January 2002, Cadernos de saude publica,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
January 2019, Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology : Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
January 2009, Emerging infectious diseases,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
April 1959, Der Hautarzt; Zeitschrift fur Dermatologie, Venerologie, und verwandte Gebiete,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
July 1993, Clinica chimica acta; international journal of clinical chemistry,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
December 2002, Cellular and molecular neurobiology,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
January 2005, Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology : Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
January 2010, Genetics and molecular research : GMR,
Eduardo Vieira Neto, and Francisco Laranjeira, and Dulce Quelhas, and Isaura Ribeiro, and Alexandre Seabra, and Nicole Mineiro, and Lilian M Carvalho, and Lúcia Lacerda, and Márcia G Ribeiro
July 2011, Emerging infectious diseases,
Copied contents to your clipboard!