Neuropsychological and quality of life outcomes in PKU patients: expert recommendations of assessment tools in Brazil / Desfechos neuropsicológicos e de qualidade de vida em pacientes com PKU: recomendações de especialistas sobre ferramentas de avaliação no Brasil

Abstract Background Phenylketonuria (PKU) is an inborn error of metabolism caused by deficient activity of phenylalanine hydroxylase. In Brazil, the National Neonatal Screening Program enables early treatment of patients with PKU, which prevents them from developing severe neurological damage and mental disabilities. However, between 20 and 30% of early-treated patients with PKU present focal cognitive deficits, including deficits in working memory, processing speed, and psychiatric symptoms such as anxiety, depression, and attention deficit hyperactivity disorder (ADHD). Therefore, age-specific neuropsychiatric and cognitive tests are important components of PKU patient care. To date, there are no officially approved guidelines or recommendations of tools in Portuguese validated for use in Brazil that could be applied to assess these parameters in patients with PKU. Objective To recommend tools validated for use in Brazil that can be used in daily clinical practice to assess quality of life and neuropsychological outcomes in patients with PKU. Methods Six Brazilian experts discussed about eligible tools based on their clinical experience, the feasibility of their use in clinical routines, and their availability in public health services. Before the meeting, an independent review of the literature was conducted to identify the currently validated tools in Brazil, using the MEDLINE and SciELO databases. Results The experts recommended nine tools to assess quality of life (Peds-QL, SF-36 or WHOQOL-bref), executive function (BRIEF or Bayley-III), IQ (SONR 2½-7[a] or WASI) and ADHD (MTA-SNAP-IV and ASRS). Conclusions These instruments may be easily incorporated into clinical practice and improve the quality of multidisciplinary care of patients with PKU.

Resumo Antecedentes A fenilcetonúria (PKU) é um erro inato do metabolismo causado pela atividade deficiente da fenilalanina hidroxilase. No Brasil, o Programa Nacional de Triagem Neonatal permite o tratamento precoce de pacientes com PKU, o que os impede de desenvolver danos neurológicos e deficiências intelectuais graves. No entanto, já foi descrito que de 20 a 30% dos pacientes tratados precocemente com PKU apresentam déficits cognitivos focais, incluindo déficits na memória de trabalho, velocidade de processamento e sintomas psiquiátricos como ansiedade, depressão e Transtorno de Déficit de Atenção e Hiperatividade (TDAH). Neste sentido, testes neuropsiquiátricos e cognitivos são componentes importantes no cuidado destes pacientes. Atualmente, não existe um compêndio científico ou recomendações de ferramentas validadas em português para avaliar a saúde mental em pacientes brasileiros com PKU. Objetivo Recomendar ferramentas validadas localmente para avaliar a qualidade de vida e aspectos neuropsicológicos de pacientes com PKU. Métodos Seis especialistas brasileiros discutiram as ferramentas mais apropriadas com base em suas experiências clínicas, a viabilidade de realizar as avaliações na rotina clínica, e o acesso às ferramentas na saúde pública. Antes da reunião, foi realizada uma revisão independente da literatura para identificar as ferramentas validadas no Brasil, utilizando as bases de dados MEDLINE e Scielo. Resultados Os especialistas recomendaram nove ferramentas para avaliar a qualidade de vida (Peds-QL, SF-36 ou WHOQOL-bref), função executiva (BRIEF ou Bayley-III), QI (SONR 2½-7[a] ou WASI) e TDAH (MTA-SNAP-IV e ASRS). Conclusões Estes instrumentos podem ser facilmente incorporados na prática clínica e melhorar a qualidade dos cuidados multidisciplinares dos pacientes com PKU.

Multiplex Snapshot minisequencing for the detection of common PAH gene mutations in Iranian patients with Phenylketonuria

Background: Phenylketonuria is a common inborn defect of amino acid metabolism in the world. This failure is caused by an autosomal recessive insufficiency of the hepatic enzyme hyperphenylalaninemia (PAH), which catalyzes the irreversible hydroxylation of phenylalanine to tyrosine. More than 1,040 different disease-causing mutations have already been identified in the PAH gene. The most prominent complication of Phenylketonuria, if not diagnosed and treated, is severe mental retardation. Hence, early diagnosis and initiation of nutritional therapy are the most significant measures in preventing this mental disorder. Given these data, we developed a simple and rapid molecular test to detect the most frequent PAH mutations. Methods: Multiplex assay was developed based on the SNaPshot minisequencing approach to simultaneously perform genotyping of the 10 mutations at the PAH gene. We optimized detection of these mutations in one multiplex PCR, followed by 10 single-nucleotide extension reactions. DNA sequencing assay was also used to verify genotyping results obtained by SNaPshot minisequencing. Result: All 10 genotypes were determined based on the position and the fluorescent color of the peaks in a single electropherogram. Sequencing results of these frequent mutations showed that by using this method, a 100% detection rate could be achieved in the Iranian population. Conclusion: SNaPshot minisequencing can be useful as a secondary test in neonatal screening for HPA in neonates with a positive screening test, and it is also suitable for carrier screening. The assay can be easily applied for accurate and time- and cost-efficient genotyping of the selected SNPs in various population.

Dificuldades alimentares em pacientes com Fenilcetonúria / Feeding difficulties in patients with Phenylketonuria

RESUMO Objetivo analisar os resultados de um instrumento que se propõe a auxiliar na identificação das dificuldades alimentares em crianças com Fenilcetonúria (PKU), em comparação a crianças sem a doença. Método estudo transversal, controlado, com amostra de conveniência composta por pacientes com PKU e por indivíduos hígidos, equiparados por idade e sexo. O convite para participação no estudo foi feito por meio de divulgação da pesquisa nas redes sociais. As respostas foram fornecidas pelos responsáveis, sendo que 46 controles e 28 pacientes participaram. Além desses, 13 responsáveis por pacientes em acompanhamento em um Ambulatório de Tratamento de Erros Inatos do Metabolismo foram convidados por ligação telefônica, sendo que 12 aceitaram o convite. Todos os participantes responderam a Escala Brasileira de Alimentação Infantil (EBAI) de forma eletrônica. Resultados foram incluídos no estudo 86 participantes, sendo 40 pacientes (mediana de idade, 2 anos; intervalo interquartil (IQR) = 2 - 4) e 46 controles (mediana de idade, 3,5 anos; IQR = 2 - 5,25). Dez (25%) pacientes e 13 (28,3%) controles apresentaram resultados compatíveis com dificuldades alimentares, demonstrando uma frequência semelhante entre os grupos. O estudo observou que os pacientes com PKU apresentaram menos autonomia alimentar (p = 0,005), foram menos amamentados (p = 0,002) e usaram mais mamadeira que os controles (p = 0,028). Conclusão a frequência de dificuldades alimentares referidas pelos cuidadores foi semelhante entre os grupos, porém as crianças com PKU demonstraram menos autonomia para se alimentar, foram menos amamentadas e usaram mais mamadeira quando comparadas com as crianças sem a doença.

ABSTRACT Purpose to analyze the results of an instrument that aims to assist in the identification of feeding difficulties in children with Phenylketonuria (PKU), compared to children without the disease. Methods cross-sectional, controlled study with a convenience sample composed of patients with PKU and healthy individuals, matched for age and sex. The invitation to participate in the study was made through the dissemination of the research on social networks. The answers were provided by the guardians, 46 controls and 28 patients agreed to participate. In addition to these, 13 guardians of patients being followed up at an Outpatient Clinic for the Treatment of Inborn Errors of Metabolism were invited by phone call, and 12 accepted the invitation. All participants answered the Brazilian Infant Feeding Scale (in Portuguese Escala Brasileira de Alimentação Infantil (EBAI)) electronically. Results the study included 86 participants, 40 patients (median of age = 2 years; interquartile range (IQR) = 2 - 4) and 46 controls (median of age = 3.5 years; IQR = 2 - 5.25). Ten (25%) patients and 13 (28.3%) controls had suspicion of feeding difficulties, demonstrating a similar frequency of feeding difficulties between groups. The study found that PKU patients had less feed autonomy (p = 0.005), were less breastfed (p = 0.002) and used more baby's bottle than controls (p = 0.028). Conclusion the frequency of feeding difficulties reported by caregivers was similar between the comparison groups, but children with PKU had less feed autonomy, were less breastfed and used more baby's bottles when compared to children without the disease.

Genetic evaluation of hyperphenylalaninemia patients with tetrahydrobiopterin deficiency in Iranian population: Identification of four novel disease-causing variants.

BACKGROUND: Hyperphenylalaninemia (HPA) is the most common inborn error of amino acid metabolism worldwide. At least 2% of HPA cases are caused by a deficiency in tetrahydrobiopterin (BH4) metabolism. Genes such as QDPR and PTS are essential in the BH4 metabolism. This study aims to identify disease-causing variants in HPA patients, which may be helpful in genetic counseling and prenatal diagnosis. METHODS: A total of 10 HPA patients were enrolled in this study. The coding and adjacent intronic regions of PTS and QDPR genes were examined using Sanger sequencing. Protein modeling was also performed for novel identified variants. RESULTS: Ten patients and a total of 20 alleles were studied, which led to the identification of 10 different variants. All variants identified in PTS and QDPR were missense, except for the c.383_407del variant in the QDPR. Also, three novel variants were identified in the QDPR, including c.79G>T, c.383_407del and c.488G>A, and a novel variant, c.65C>G, in the PTS. CONCLUSIONS: Despite the genetic similarities in the disease-causing variants, differences were observed in the Asian and European populations with our populations; As a result, similar but more extensive studies are needed to investigate the distribution of disease-causing variants in genes involved in non-PKU hyperphenylalaninemia.

Brazilian Food Reference Guide for Phenylalanine Content: A Study Based on the Perception of PKU Patients and Health Providers

Abstract The mainstay of management of phenylketonuria (PKU) is restriction of dietary phenylalanine (Phe) intake. The present study sought to assess the perception and understanding of health care providers and lay users (patients/family members/caregivers) regarding the national reference database for checking the Phe content of foods, provided by the Brazilian Health Regulatory Agency (Anvisa), whose data are presented in the Table of Phenylalanine Content of Foods (TCFA-Anvisa) and recently in the Phenylalanine Content of Foods Dashboard (PCCFA-Anvisa); and to identify factors which interfere with the usability of these resources. Two online questionnaires, one for providers (n=33) and another for lay users (n=194), were used to collect sociodemographic information, knowledge about dietary management of PKU, sources of information about the Phe content of foods, and perception and understanding of the Anvisa tools. TCFA-Anvisa and PCCFA-Anvisa were not used as main sources of information by either group. Among the participants who had used these tools (15 providers;35 lay users), most considered the PCCFA-Anvisa to be superior or partially superior to the TCFA-Anvisa. The main limitations reported were related to layout and limited variety of foods. We suggest that the limitations identified in this study be considered for future improvement of these resources.

Metabolic control and body composition of children and adolescents with phenylketonuria / Controle metabólico e composição corporal de crianças e adolescentes com diagnóstico neonatal de fenilcetonúria

ABSTRACT Objective: To characterize metabolic control and verify whether it has any relation with socioeconomic, demographic, and body composition variables in children and adolescents with phenylketonuria (PKU) diagnosed in the neonatal period. Methods: This cohort study collected retrospective data of 53 phenylketonuric children and adolescents. Data on family income, housing, and mother's age and schooling level were collected, and anthropometric measures of body composition and distribution were taken. All dosages of phenylalanine (Phe) from the last five years (2015-2019) were evaluated and classified regarding their adequacy (cutoffs: 0-12 years: 2-6 mg/dL; 12-19 years: 2-10 mg/dL). Adequate metabolic control was considered if ≥7%) of the dosages were within desired ranges. Results: The mean (±standard deviation) age in the last year was 10.1±4.6 years. Most of them were under 12 years old (33/53; 62.3%) and had the classic form of the disease (39/53; 73.6%). Better metabolic control was observed among adolescents (68.4 versus 51.4%; p=0.019). Overweight was found in 9/53 (17%) and higher serum Phe levels (p<0.001) were found in this group of patients. Metabolic control with 70% or more Phe level adequacy decreased along with the arm muscle area (AMA) (ptendency=0.042), being 70.0% among those with low reserve (low AMA), and 18.5% among those with excessive reserve (high AMA). Conclusions: Adequate metabolic control was observed in most patients. The findings suggest that, in this sample, the levels of phenylalanine may be related to changes in body composition.

RESUMO Objetivo: Caracterizar o controle metabólico e verificar se existe relação entre ele, variáveis socioeconômicas, demográficas e composição corporal de crianças e adolescentes com fenilcetonúria (FNC) diagnosticada no período neonatal. Métodos: Coorte com coleta retrospectiva de dados de 53 crianças e adolescentes fenilcetonúricos. Foram coletados dados de renda familiar, moradia, idade e escolaridade materna e realizaram-se medidas antropométricas de composição e distribuição corporal. Todas as dosagens de fenilalanina (Fal) dos últimos cinco anos (2015-2019) foram avaliadas e classificadas quanto à adequação (cortes: 0-12 anos: 2-6 mg/dL; 12-19 anos: 2-10 mg/dL). A proporção de dosagens adequadas ≥70% foi considerada como controle metabólico adequado. Resultados: A média (±desvio padrão) de idade, no último ano, foi de 10,1±4,6 anos. A maioria tinha menos de 12 anos (33/53; 62,3%) e apresentava a forma clássica da doença (39/53; 73,6%). Observou-se melhor controle metabólico entre os adolescentes (68,4 vs. 51,4%; p=0,019). Excesso de peso foi encontrado em 9/53 (17%) e maiores níveis séricos de Fal foram descritos nesse grupo (p<0,001). O percentual de controle metabólico com 70% ou mais de adequação dos níveis de Fal foi decrescente de acordo com a área muscular do braço (AMB; ptendência=0,042), sendo de 70% entre os de baixa reserva (AMB reduzida) e de 18,5% entre os com excesso (AMB elevada). Conclusões: Observou-se controle metabólico adequado na maioria dos avaliados e os achados sugerem que, nesta amostra, os níveis de fenilalanina podem estar relacionados com alterações da composição corporal.

[Screening of phenylketonuria and analysis of phenylalanine hydroxylase gene in 380 996 newborns from Hainan province].

Objective: To investigate the incidence of phenylketonuria and distribution characteristics of phenylalanine hydroxylase (PAH) gene in newborns from Hainan province. Methods: Dry blood spot specimens of heels from 380 996 newborns in Hainan province from January 2017 to December 2019 were collected. Phenylalanine (Phe) concentrations in these dry blood spots were measured by the fluorescence method to screen phenylketonuria (PKU). A second dry blood spot sample will be collected if suspicious samples were detected after initial screening. Tandem mass spectrometry were used to detect the concentrations of Phe and tyrosine. Urine samples of the suspected newborns were sent out for urotrexate spectrum analysis and tetrahydrobiopterin loading test. PCR and flow-through rapid hybridization method were employed to detect PAH gene mutations. Meanwhile, peripheral blood samples of suspicious newborns of PKU and their parents were collected to perform gene sequencing. Results: Among the 380 996 newborns, 39 were suspected and 14 were diagnosed with PKU, including 11 cases of PAH deficiency and 3 cases of tetrahydrobiopterin deficiency. Of 14 confirmed cases, there were 8 male cases and 6 female cases. In the newborn population of Hainan province, the annual incidence of PKU was 1.22/100 000. Thirteen PAH gene mutations were detected in confirmed cases: c.728G>A, c.158G>A, c.1238G>C, c.611A>G, c.1068C>A, c.706+5G>A, c.740G>T, c.1081A>T, c.793T>G, c.1223G>A, c.721C>T, c.331C>T and c.1174T>A. Conclusions: PKU has a high incidence in newborn population of Hainan province in the past three years. The PAH gene has a wide spectrum of mutations. Two rare mutations were also found: c.793T>G and c.706+5G>A.

Sobrepeso/obesidade e doença hepática gordurosa não alcoólica em adolescentes com fenilcetonúria / Overweight/obesity and non alcoholic fat liver disease in adolescents with phenylketonuria

Introdução: A fenilcetonúria (PKU) é um erro inato do metabolismo, devido à perda ou diminuição da atividade da enzima fenilalanina hidroxilase. A dieta, com restrição de proteínas naturais e uso de fórmula de aminoácidos isenta em fenilalanina tem papel chave em seu tratamento. As peculiaridades da dieta têm levado à hipótese de predisposição ao sobrepeso/obesidade que, por outro lado é suspeito de predispor à doença hepática gordurosa não alcoólica (DHGNA). Teriam adolescentes com PKU maior predisposição ao desenvolvimento de sobrepeso/obesidade e à DHGNA? Objetivo: Avaliar sobrepeso/obesidade e DHGNA em adolescentes com PKU em tratamento dietético exclusivo. Métodos: Estudo transversal com 101 adolescentes com PKU entre 10 anos e 20 anos incompletos entre 2017-2018. Foram realizadas avaliações antropométricas, bioquímicas, determinação do consumo alimentar e ultrassom abdominal, com classificação do índice hepatorenal. Os pacientes foram divididos em dois grupos, de acordo com seu estado nutricional: um com os indivíduos com sobrepeso/obesidade, outro com eutrofia/baixo IMC. Foi constituído subgrupo com adolescentes de 13-17 anos para comparação com prevalência do sobrepeso/obesidade em escolares sadios, da mesma idade. Resultados: A prevalência de sobrepeso/obesidade foi de 27,7% e não houve predominância de sexos. A análise multivariada indicou concentrações sanguíneas elevadas de fenilalanina, de LDL-colesterol e elevação do índice HOMA como fatores preditores e aumento da idade como fator protetor do sobrepeso/obesidade. A comparação da prevalência de sobrepeso/obesidade entre os 46 pacientes entre 13-17 anos com escolares da mesma idade não rejeitou a hipótese de igualdade. A avaliação do índice hepatorenal detectou presença de DHGNA em 26 (25,7%) adolescentes, sem distinção entre sexos ou associação com sobrepeso/obesidade, sugerindo que a PKU e/ou a dieta podem contribuir para a DHGNA. O modelo final da análise multivariada, apresentou sensibilidade de 26,1% e especificidade de 94,7%, indicando a necessidade de estudar outras variáveis. A especificidade do modelo final sugeriu uma possibilidade menor de DHGNA naqueles com idade maior, níveis de fosfatase alcalina normal ou elevada, menor consumo de carboidratos e lipídios e consumo adequado de proteínas. Conclusão: A prevalência de sobrepeso/obesidade dos adolescentes com PKU foi semelhante à encontrada entre os adolescentes sem a doença. Concentrações elevadas de Phe, e LDL colesterol e índice HOMA acima da referência foram fatores preditores da mesma e idade mais elevada fator protetor. A PKU e/ou a dieta utilizada em seu tratamento podem representar risco de DHGNA, independentemente do sexo e do estado nutricional. A especificidade do modelo final sugeriu a possibilidade de DHGNA menor naqueles com idade maior, níveis de fosfatase alcalina normal/elevada, menor consumo de carboidratos e lipídios e consumo adequado de proteínas.

Overweight and associated factors in children and adolescents with phenylketonuria: a systematic review / Excesso de peso e fatores associados em crianças e adolescentes com fenilcetonúria: uma revisão sistemática

ABSTRACT Objective: To verify the occurrence of overweight in children and adolescents with phenylketonuria and to identify possible causal factors. Data sources: A systematic review was performed in the SciELO, PubMed and VHL databases using the descriptors "Phenylketonurias", "Overweight", "Child" and "Adolescent". Original articles conducted with children and adolescents, published between 2008 and 2018 in Portuguese, English or Spanish languages were included. Data synthesis: A total of 16 articles were identified and, after screening procedures, 6 studies were selected for the review. Overweight in children and adolescents with phenylketonuria was a frequent occurence in the studies included in this review, ranging from 7.8 to 32.6%. The female sex was the most affected by the nutritional disorder. Furthermore, a high caloric intake combined with a lack of stimuli to practice physical activities were main factors associated with the excessive weight in the population of interest. Conclusions: Excess weight can be considered a common outcome in children and adolescents with phenylketonuria. It is mainly caused by inadequate food consumption and sedentary lifestyle. The importance of early identification of nutritional disturbances in children and adolescents with phenylketonuria should be emphasized, in order to prevent associated chronic diseases and to promote health by encouraging continued healthy eating habits and the regular practice of physical exercises.

RESUMO Objetivo: Verificar a ocorrência de excesso de peso em crianças e adolescentes com fenilcetonúria e identificar possíveis fatores causais. Fontes de dados: Revisão sistemática realizada nas bases de dados Scientific Eletronic Library Online (SciELO), Publisher Medline (PubMed) e Biblioteca Virtual em Saúde (BVS) com os descritores "Phenylketonurias", "Overweight", "Child" e "Adolescent". Foram incluídos artigos originais sobre crianças e adolescentes, publicados entre 2008 e 2018 nos idiomas português, inglês ou espanhol. Síntese dos dados: Foram identificados 16 artigos e, após aplicação dos procedimentos de seleção, 6 estudos foram selecionados para compor a revisão. O excesso de peso em crianças e adolescentes com fenilcetonúria foi evento frequente nos estudos incluídos na presente revisão, variando de 7,8 a 32,6%. Aponta-se o sexo feminino como o grupo mais acometido pelo distúrbio nutricional. O principal fator associado ao excesso de peso na população de interesse na população de interesse foi o consumo calórico elevado aliado à falta de estímulos para a prática de atividades físicas. Conclusões: O excesso de peso pode ser considerado um desfecho comum em crianças e adolescentes com fenilcetonúria, sendo ocasionado principalmente pelo consumo alimentar inadequado e pelo sedentarismo. Salienta-se a importância da identificação precoce de agravos nutricionais em crianças e adolescentes fenilcetonúricos, a fim de prevenir doenças crônicas associadas e promover a saúde, com incentivo à manutenção de hábitos alimentares saudáveis e à prática regular de exercícios físicos.

Spectrum of Phenylalanine Hydroxylase Gene Mutations in Hamadan and Lorestan Provinces of Iran and Their Associations with Variable Number of Tandem Repeat Alleles.

Phenylketonuria (PKU) is one of the most common known inherited metabolic diseases. The present study aimed to investigate the status of molecular defects in phenylalanine hydroxylase (PAH) gene in western Iranian PKU patients (predominantly from Kermanshah, Hamadan, and Lorestan provinces) during 2014-2016. Additionally, the results were compared with similar studies in Iran. Nucleotide sequence analysis of all 13 exons and their flanking intronic regions of the PAH gene was performed in 18 western Iranian PKU patients. Moreover, a variable number of tandem repeat (VNTR) located in the PAH gene was studied. The results revealed a mutational spectrum encompassing 11 distinct mutations distributed along the PAH gene sequence on 34 of the 36 mutant alleles (diagnostic efficiency of 94.4%). Also, four PAH VNTR alleles (with repeats of 3, 7, 8 and 9) were detected. The three most frequent mutations were IVS9+5G>A, IVS7-5T>C, and p.P281L with the frequency of 27.8%, 11%, and 11%, respectively. The results showed that there is not only a consanguineous relation, but also a difference in PAH characters of mutations between Kermanshah and the other two parts of western Iran (Hamadan and Lorestan). Also, it seems that the spectrum of mutations in western Iran is relatively distinct from other parts of the country, suggesting that this region might be a special PAH gene distribution region. Moreover, our findings can be useful in the identification of genotype to phenotype relationship in patients, and provide future abilities for confirmatory diagnostic testing, prognosis, and predict the severity of PKU patients.

Outcomes of children with Phenylketonuria detected by newborn screening program / 中华全科医师杂志

Objective To evaluate the outcomes of children with Phenylketonuria(PKU)detected by newborn screening program.Methods One hundred and two children with PKU were detected and diagnosed in Shanxi Newborn Screening Center from June 2004 to September 2014.All children with PKU were followed up until December 2015.During the follow-up,the Phenylalanine(Phe)levels,physical and intellectual development, nutrition status of those children were monitored.Results Among 102 PKU children,there were 96(94.12%)with normal physical development,and 93(91.18%)with normal DQ/IQ.The average DQ or IQ score in children who started the therapy before 1 month was higher than that in those who started after 1 month old(93.07 ±9.50 vs.87.39 ±10.99,t=3.09, P=0.00).Among these children 82.47%(80/97)had zinc deficiency and 31.46%(28/89)had dyslipidemia; and the normal Phe concentration rate was(59.73 ±19.03)%.The intellectual development level was negatively correlated with the age of starting therapy(r=-0.25, P=0.01), positively correlated with the education levels of his/her father(r=0.21,P=0.03)and mother(r=0.23, P=0.02).And the intellectual development was better in urban areas than that in rural areas.Conclusions With the standardized treatment, the physical and intellectual development of children with PKU can basically reach normal levels,and the earlier treatment can make better therapeutic effect.

Prenatal diagnosis and PAH gene mutations in 55 pedigrees with phenylketonuria / 中华围产医学杂志

Objective To investigate phenylalanine hydroxylase ( PA H ) gene mutations and to perform prenatal diagnosis in 55 pedigrees with classical phenylketonuria (PKU). Methods Subjects of this study were 55 probands diagnosed with PKU in the Gansu Provincial Maternal and Child Health Care Hospital from 2013 to 2017 and their pedigrees. Sanger sequencing/Multiplex ligation-dependent probe amplification (MLPA) was used to investigate PA H gene mutations in these probands and their parents. Sanger sequencing/MLPA, linkage analysis of three common short tandem repeats (STR) including PAH-26, PAH-STR and PAH-32 in the PA H gene and paternity testing were used in combination for prenatal diagnosis of 60 fetuses in the 55 pedigrees. Results Among the 110 alleles in the 55 probands, 108 mutant alleles (98.2%) were found by Sanger sequencing. The 108 mutant alleles located in 38 regions resulting in 22 missense mutations, nine splice site mutations, five nonsense mutations and two microdeletion. The most common mutations were c.728G>A (22.2%, 24/108), c.442-1G>A (5.6%, 6/108), c.611A>G (5.6%, 6/108), c.764T>C (5.6%, 6/108), c.1068C>A (5.6%, 6/108) and c.331C>T (4.6%, 5/108). Loss of heterozygosity in 4-5 and 4-7 exons were detected by MLPA in two probands, in which only one mutation was unidentified. Prenatal diagnosis for the 60 fetuses were successfully performed. Among them, 17 fetuses (28.3%) were affected, 29 fetuses (48.3%) were heterozygous carriers and fetuses 14(23.4%) were unaffected ones. Conclusions Combination of Sanger sequencing/MLPA, linkage analysis and paternity testing could provide accurate prenatal diagnosis in pedigrees with PKU.

Comparison of different methods for measuring the phenylalanine concentration of phenylketonuria patients in dried blood spots / 中华检验医学杂志

Objective To compare the phenylalanine(Phe)concentration in the sample of dried blood spot,measured by four different methods:fluorescence assay,tandem mass spectrometry(MS/MS), including MS/MS Derivatized,MS/MS Non-Derivatized and MS/MS-Standard Curve.Methods A total of 204 dried blood spot(DBS)samples of phenylketonuria(PKU)patients from Shanghai Xinhua Hospital were collected in this study.Phe concentration in DBS was measured by fluorescence assay and MS /MS assay,including MS/MS Derivatized, MS/MS Non-Derivatized and MS/MS-Standard Curve.The samples were divided into low, middle and high concentration groups according to Phe concentration, which were under the 360 μmol/L,between 360 and 600 μmol/L,and over 600 μmol/L respectively.The differences among the groups were analyzed by consistency check and non-parametric test.Results The within-day and between-day precisions of MS/MS-Standard Curve assay were 4.0%-7.2%,the recoveries were 93.2%-97.3%.Consistency check showed that less than 8.1%of Phe value were out of the 95%limit of agreement among these four methods.In the low and middle concentration groups,the quartile of Phe value measured by fluorescence assay,MS/MS Standard Curve and MS/MS Derivatized were 176(118,251)μmol/L,174 (94,273)μmol/L,153(94,242)μmol/L; and 540(478,578)μmol/L,485(414,529)μmol/L,466(402,513)μmol/L,respectively.Phe value measured by fluorescence assay was significantly higher than that by MS/MS Standard Curve,the difference was 4.8%-9.0%,(Z=-3.787 to -2.674,P<0.01). Phe value obtained from MS/MS Non-Derivatized was less than that by MS/MS-Standard Curve, the difference was 3.9%-5.2%,(Z=-7.474 to -5.747,P<0.01).In the high concentration group,the quartile of Phe value measured by MS/MS-Standard Curve, MS/MS Derivatized, MS/MS Non-Derivatized and fluorescence assay were 807(695,924)μmol/L,700(575,785)μmol/L,680(623,771)μmol/L and 711(674, 794)μmol/L, respectively.Phe value obtained from MS/MS Standard Curve was significantly higher than those from the other methods and the difference was 10.9% -16.2%,(Z=-4.458 to-4.356,P<0.01).Conclusions The MS/MS Standard Curve assay showed good specificity and accuracy.These four assays displayed good agreement.Although there was difference in measuring the Phe concentration among these methods, they could be used in blood Phe concentration monitoring for PKU patients.

Fenilcetonúria: aspectos genéticos, diagnóstico e tratamento / Phenylketonuria: genetic aspects, diagnosis and treatment

A fenilcetonúria é uma doença genética e metabólica, com bom prognóstico caso seja detectada e tratada precocemente. É a mais frequente entre os distúrbios metabólicos com significativa implicação clínica. Ela é detectada precocemente pelo Teste do Pezinho na triagem neonatal, e o tratamento padrão consiste em dieta restritiva. Este estudo teve por finalidade informar e atualizar os profissionais da área da saúde sobre base genético-clínica da fenilcetonúria, com destaque para sua etiologia e aconselhamento genético; diagnóstico com enfoque no histórico da triagem neonatal; e tratamento − em especial o dietético. Foi utilizada como fonte a literatura científica especializada, publicada principalmente nos últimos 5 anos.(AU)

Phenylketonuria is a genetic and metabolic disease, with good prognosis if early detected and treated. It is the most frequent among metabolic disorders, with significant clinical implications. It is detected early by Guthrie test in the neonatal screening, and the standard treatment consists of a restrictive diet. This study is aimed at informing and updating healthcare professionals on: 1) genetic-clinical basis of phenylketonuria, highlighting its etiology and genetic counseling, 2) diagnosis focusing on the history of newborn screening, and 3) treatment, in particular the dietetic one. The specialized scientific literature, particularly that published in the last five years, was used as a source.(AU)

Incidence of Neonatal Hyperphenylalaninemia Based on High-performance Liquid Chromatography Confirmatory Technique in Mazandaran Province, Northern Iran (2007-2015).

BACKGROUND: Classic phenylketonuria (PKU) is a metabolic disorder. The purpose of this study was to assess epidemiological factors of PKU phenotypes in a neonatal screening program for Mazandaran, Iran. METHODS: In this descriptive-retrospective study from 2007 to 2015, neonates PKU level was conducted by phenylalanine level based on a biochemical technique by ELISA and then by confirmatory methods high performance liquid chromatography. RESULTS: Of the 407,244 screened newborns (48.7% girls and 51.3% boys), 14 girls and 13 boys were diagnosed definitely from 465 suspicious cases of PKU. The incidence of PKU was 0.66 in 10,000, which was noted in different severity (severe PKU - 1:67,874, mild PKU - 1:45,249, and HPA - 1:33,937). In addition, we did not detect any cases of nonclassic PKU. CONCLUSIONS: Although the consanguineous marriage pattern is a major cause of hyperphenylalaninemia (HPA) particularly in Iranian, there was no significant difference between groups in this study. Now, screening should be executed for all of the family that they have the familial history of PKU in Iran. According to varies actual of prevalence and incidence rate of PKU reported a real patient and taking PKU with mild PKU and HPA, it is recommended, the will provide the PKU reports based on the severity of the disease.

A Novel Variant in the PAH Gene Causing Phenylketonuria in an Iranian Pedigree.

BACKGROUND: Phenylalanine hydroxylase (PAH) gene is the well-known causative gene for classic Phenylketonuria (PKU) (OMIM#261600) disease, with more than 500 reported mutations. Through this study, a novel mutation in the PAH gene in an Iranian pedigree with phenylketonuria was introduced. METHODS: A consanguineous family with a 10-year old affected girl was referred for genetic analysis. Mutation screening of all exons and exon-intron boundaries was performed by Sanger sequencing, and mini haplotype analysis was carried out by genotyping of Short Tandem Repeat (STR) and Variable Number Tandem Repeat (VNTR) alleles. RESULTS: Mutation analysis revealed a novel homozygous insertion of a single adenine nucleotide at position 335 in exon 3 of the PAH gene. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, the change is interpreted as a pathogenic mutation which produces a premature termination signal (TAA) at codon 113 according to in silico assessments. The mini haplotype analysis showed that this mutation was linked to STR (15) -VNTR (3). CONCLUSION: In this study, a novel mutation was reported in a patient who had PKU symptoms without any previously reported mutations in the PAH gene (NM_000277.1:p.Asp112Glufs*2) that can be responsible for the classical PKU phenotype in the Iranian population. Detection of novel mutations indicates notable allelic heterogeneity of the PAH locus among this population.

Identification of a Novel Mutation in the PAH Gene in an Iranian Phenylketonuria Family: A Case Report.

Phenylketonuria (PKU) is an inborn error of amino acid metabolism with an autosomal recessive inheritance caused in most cases by mutations in the phenylalanine hydroxylase (PAH) gene. PKU has wide allelic heterogeneity. Here we report a novel heterozygous substitution (c.1223G>T (p.Arg408Leu)) in the PAH gene in an Iranian PKU family. The patient was 19-yr-old female with diagnosis of moderate PKU referred to Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran for genetic counseling/analysis in April 2015. We used PCR-Sequencing to identify any sequence variations in the PAH gene.

[Phenotypic and molecular characterization of a Colombian family with phenylketonuria].

INTRODUCTION: Phenylketonuria is a metabolic disorder characterized by severe neurological involvement and behavioral disorder, whose early diagnosis enables an effective treatment to avoid disease sequelae, thus changing the prognosis. Objective: To characterize a family with phenylketonuria in Colombia at clinical, biochemical and molecular levels. Materials and methods: The population consisted of seven individuals of a consanguineous family with four children with suggestive symptoms of phenylketonuria. After signing an informed consent, blood and urine samples were taken for colorimetric tests and high performance liquid and thin layer chromatographies. DNA extraction and sequencing of the 13 exons of the PAH gene were performed in all subjects. We designed primers for each exon with the Primer 3 software using automatic sequencing equipment Abiprism 3100 Avant. Sequences were analyzed using the SeqScape, v2.0, software. Results: We described the clinical and molecular characteristics of a Colombian family with phenylketonuria and confirmed the presence of the mutation c.398_401delATCA. We established a genotype-phenotype correlation, highlighting the interesting clinical variability found among the affected patients despite having the same mutation in all of them. Conclusions: Early recognition of this disease is very important to prevent its neurological and psychological sequelae, given that patients reach old age without diagnosis or proper management.

Caracterización fenotípica y molecular de una familia colombiana con fenilcetonuria / Phenotypic and molecular characterization of a Colombian family with phenylketonuria

Introducción. La fenilcetonuria es un trastorno metabólico caracterizado por un compromiso neurológico grave y por alteraciones del comportamiento. Su diagnóstico temprano permite establecer un tratamiento efectivo que evita las secuelas y modifica el pronóstico. Objetivo. Caracterizar a una familia con fenilcetonuria en Colombia, a nivel clínico, bioquímico y molecular. Materiales y métodos. Se estudió una población de siete individuos de una familia consanguínea en la que cuatro hijos presentaban signos clínicos sugestivos de fenilcetonuria. Una vez firmado el consentimiento informado, se tomaron muestras de sangre y orina para las pruebas colorimétricas, la cromatografía de capa fina y la cromatografía líquida de alta eficacia. Se extrajo el ADN y se secuenciaron los 13 exones del gen PAH de todos los sujetos estudiados. Se diseñaron iniciadores para cada exón con el programa Primer 3; la secuenciación automática se hizo con el equipo Abiprism 3100 Avant y, el análisis de las secuencias, con el programa SeqScape v2.0. Resultados. Se describieron las características clínicas y moleculares de una familia colombiana con fenilcetonuria en la que se identificó la mutación c.398_401delATCA; se presentó una correlación fenotipo-genotipo con una interesante variabilidad clínica entre los afectados, a pesar de tener la misma mutación. Conclusiones. Es importante el reconocimiento temprano de esta enfermedad para evitar sus secuelas neurológicas y psicológicas, pues los pacientes llegan a edades avanzadas sin diagnóstico ni tratamiento adecuados.

Introduction: Phenylketonuria is a metabolic disorder characterized by severe neurological involvement and behavioral disorder, whose early diagnosis enables an effective treatment to avoid disease sequelae, thus changing the prognosis. Objective: To characterize a family with phenylketonuria in Colombia at clinical, biochemical and molecular levels. Materials and methods: The population consisted of seven individuals of a consanguineous family with four children with suggestive symptoms of phenylketonuria. After signing an informed consent, blood and urine samples were taken for colorimetric tests and high performance liquid and thin layer chromatographies. DNA extraction and sequencing of the 13 exons of the PAH gene were performed in all subjects. We designed primers for each exon with the Primer 3 software using automatic sequencing equipment Abiprism 3100 Avant. Sequences were analyzed using the SeqScape, v2.0, software. Results: We described the clinical and molecular characteristics of a Colombian family with phenylketonuria and confirmed the presence of the mutation c.398_401delATCA. We established a genotype-phenotype correlation, highlighting the interesting clinical variability found among the affected patients despite having the same mutation in all of them. Conclusions: Early recognition of this disease is very important to prevent its neurological and psychological sequelae, given that patients reach old age without diagnosis or proper management.