Importance of Studying Older Siblings of Patients Identified by Newborn Screening: a Single-Center Experience in Mexico

Abstract Introduction: Any abnormal newborn screening (NBS) test should be subjected to appropriate diagnostic tests and should be followed. Once the newborn has been diagnosed and treated, the family should receive comprehensive genetic services. Aim: To present the experience of studying older siblings of patients with inborn errors of metabolism (IEM) identified by NBS in a single-national follow-up reference center. Methods: A retrospective analysis of medical files of the IEM patients detected by NBS was conducted. All those older siblings who tested positive for the same IEM of the patient detected by newborn screening were included. Results: A total of 26 positive siblings from 18 families with seven different IEM were found (phenylketonuria, argininemia, glucose-6-phosphate dehydrogenase deficiency, 3-methylcrotonyl-CoA carboxylase deficiency, dihydropteridine reductase deficiency, tyrosinemia type 3, and medium chain acyl-CoA dehydrogenase deficiency). The age range of the affected siblings was 2 to 19 years old, with a mean age of 8.5 years. Ten older siblings (38.5%) had clinical consequences for the disease, including severe intellectual disability. Conclusions: It is necessary to study older siblings, and family history and genetic counseling of all NBS-detected families should be recommended, especially in countries where expanded NBS programs are beginning.

Clinical profiles and outcomes of the most common inherited metabolic diseases in the Philippines: A review of the National Institutes of Health - Institute of Human Genetics Metabolic Registry

@#<p><strong>OBJECTIVE:</strong> This study reviewed the profiles and outcomes of patients diagnosed to have the five most common inherited metabolic diseases (IMDs) in the Metabolic Registry of the National Institutes of Health - Institute of Human Genetics (NIH-IHG) from 1999 to 2016.</p><p><br /><strong>METHODS: </strong>The medical records of the patients diagnosed with the following inherited metabolic diseases were reviewed: maple syrup urine disease (MSUD), galactosemia, hyperphenylalaninemias (including classical phenylketonuria, mild hyperphenylalaninemia, and pterin defects), mucopolysaccharidoses (MPS), and adrenoleukodystrophy (ALD).</p><p><br /><strong>RESULTS:</strong> There was a total of 567 patients with IMDs, giving a minimum estimated burden of 1.9 per 100,000 livebirths (1:51,760). Clinical presentations were similar to those reported in literature. Majority of the cases of galactosemia and hyperphenylalaninemias presented with a positive newborn screening result. The local prevalence of MSUD and MPS II were higher compared to international data, which may be explained by reported founder mutations among Filipinos. Majority of the patients with IMDs were diagnosed late leading to preventable developmental delay or intellectual disability and death. Majority of patients with MSUD (80.6%) and MPS (94.7%) had intellectual disability or developmental delay. Mortality was 50.5% among patients with MSUD and 100% among patients with adrenoleukodystrophy.</p><p><br /><strong>CONCLUSION: </strong>There is a diversity of IMDs present in the country. A long-term strategic plan, such as the full implementation of the National Rare Disease Act, is foreseen to improve access to comprehensive healthcare and quality of life of patients with IMDs in the country.</p>

Characteristics of gene variants among patients with hyperphenylalaninemia from Quanzhou region of Fujian province / 中华医学遗传学杂志

Objective@#To explore the spectrum of genetic variants among patients with hyperphenylalaninemia (HPA) from Quanzhou area of Fujian province.@*Methods@#For 63 children affected with HPA, next generation sequencing was used to identify potential variants in PAH, PTS, PCBD1, QDPR, SPR and GCH1 genes.@*Results@#Fifty two variants underlying phenylalanine hydroxylase deficiency (PAHD) and 13 variants underlying 6-pyruvoyl tetrahydropterin synthase deficiency (PTPSD) were identified. Two patients carried variants of both PAH and PTS genes. The most common variants of the PAH gene were R53H (21.69%), R241C (18.07%), R243Q (12.05%) and EX6-96A>G (7.23%), which were mainly located in exons 7 (32.53%), 2 (21.69%), 6 (9.64%) and 12 (9.64%). The L227M variant of the PAH gene was unreported previously. N52S (35.00%), P87S (25.00%), IVS1-291A>G (10.00%) and T67M (10.00%) variants were the most common variants for the PTS gene and were mainly located in exons 2 (35.00%) and 5 (35.00%).@*Conclusion@#The variant spectrum underlying HPA in Quanzhou area showed a geographical specificity. A novel variant of the PAH gene (L227M) has been detected.

Deficiencia de fenilalanina hidroxilasa: espectro clínico y estado actual del diagnóstico en colombia / Phenylalanine hydroxylase deficiency: clinical spectrum and current diagnosis in colombia

RESUMEN Las mutaciones del gen PAH generan deficiencia de la enzima fenilalanina hidroxilasa. Su actividad final varía desde una actividad casi nula o indetectable en la fenilcetonuria clásica hasta una actividad residual del 10 al 35% de la normal. Esta alteración corresponde al error innato del metabolismo de los aminoácidos más frecuente, afectando a 1 de cada 10.000 personas. Las diferentes cantidades de fenilalanina en sangre se traducen en un espectro amplio de manifestaciones clínicas que incluyen retraso global del desarrollo, discapacidad intelectual, convulsiones, rasgos autistas y comportamiento agresivo en los casos más graves. El diagnóstico temprano a través de los programas de tamizaje neonatal se considera prioritario pues las intervenciones oportunas evitan el daño del sistema nervioso central. Conclusiones: El diagnóstico en Colombia es tardío, las intervenciones realizadas a partir de ese momento son fútiles pues el deterioro cognitivo es irreparable, por lo tanto es imperativa la realización de pruebas diagnósticas tempranas cuando aún las intervenciones médicas pueden impactar la mejoría clínica del paciente con disminución importante de la morbilidad propia de esta patología, convirtiéndose en una necesidad la ampliación del programa de tamizaje neonatal, el cual estaría amparado bajo la ley colombiana de enfermedades huérfanas.

ABSTRACT Mutations in the PAH gene generate phenylalanine hydroxylase enzyme deficiency. Its final activity varies from almost null or undetectable in classical phenylketonuria to a residual activity of 10 to 35% of normal activity. This alteration corresponds to the innate more frequent error of the metabolism of the amino acids, affecting 1 of every 10,000 people. Different amounts of phenylalanine in blood translate into a broad spectrum of clinical manifestations including global developmental delay, intellectual disability, seizures, autistic traits, and aggressive behavior in the most severe cases. Early diagnosis through neonatal screening programs is considered a priority because timely interventions avoid damage to the central nervous system. Conclusions: The diagnosis in Colombia is belated, the interventions made from that moment are futile because the cognitive deterioration is irreparable. Therefore, it is imperative to carry out early diagnostic tests when medical interventions can still impact the clinical improvement of the patient with an important decrease of the morbidity characteristic of this pathology, making it necessary to expand the neonatal screening program which would be protected under the Colombian law of orphan diseases.

Analysis of types and metabolic profiles of hyperphenylalaninemia / 中华实用儿科临床杂志

Objective To study the characteristics of hyperphenylalaninemia (HPA) and the differences in blood and urine metabolic index and their correlation.Methods A total of 137 patients with HPA diagnosed by the Pediatric Inherit Metabolism and Endocrine Department,Guangdong Women and Children's Hospital,Guangzhou Medical University from January 2014 to June 2017,were enrolled.Tandem mass spectrometry (MS/MS),gas chromatography/ mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) were used to analyze the concentration of blood and urine metabolites in children,and the patients were divided into different groups according to the drug load test of tetrahydrobiopterin (BH4) and dihydrobiopterindine reductase (DHPR) deficiency.The HPA metabolite analysis of horizontal concentration by statistical differences and correlation analysis were performed.Results Among the 137 cases of HPA,there were 101 cases (73.7％) of phenylalanine hydroxylase deficiency (PAH),and among them 21 cases (15.3％) were classic phenylketonuria (PKU),37 cases were mild PKU (27.0％),43 cases (31.4％) wcrc mild HPA.Thcrc were 22 cases (16.1％) with BH4 reaction,and 79 cases (57.7％) of non-reactive type.Besides,there were 36 cases (26.3％) of tetrahydrobiopterin deficiency (BH4 D),of which 6-pyruvoyl tetrahydropterin synthase deficiency (PTPS) in 34 cases (24.8％) and dihydrobiopterindine reductase deficiency (DHPR) in 2 cases (1.5％).Urinary phenylacetic acid (r =0.673,P ＜ 0.01),phenyllactic acid (r =0.736,P ＜ 0.01),phenylpyruvic acid (r =0.642,P ＜ 0.01) were significantly correlated with blood phenylalanine (Phe) concentration,and the neopterin (N) (r =0.442,P ＜ 0.01) and biopterin (B) (r =0.398,P ＜ 0.01) had low correlation.Urinary phenylacetic acid,phenyllactic acid and phenylpyruvic acid had no correlation with urinary pterin.There were significant differences among PTPS deficiency group,BH4 response type,and non-reactive type(all P ＜ 0.05),but no significant difference between the BH4 reaction type and the non-reactive group (P ＞ 0.05).Conclusions Through the analysis of the different types of HPA metabolic profiles,it can help to master the incidence and characteristics in the region,within a certain concentration range of blood Phe,the phenylacetic acid,phenyllactic acid,phenylpyruvic acid should not be tested by GC-MS alone.Uterine erythropoietin analysis of BH4D classification and identification of BH4 reaction,non-reactive PKU have a supporting role,so master the metabolic index of various types of concentration and relevance of HPA,it can provide basis for early diagnosis,accurate treatment and follow-up.

Progress in molecular genetics of hyperphenylalanemia / 国际儿科学杂志

Hyperphenylalaninemia is a common group of inherited metabolic diseases.It is characterized by the increased concentration of plasma phenylalanine.The metabolism of phenylalanine requires phenylalanine hydroxylase and coenzyme tetrahydrobiopterin.These enzymes cannot function normally if there is any mutation in their encoding genes.Children suffering from hyperphenylalaninemia without promptly treatment may present mental development delay and other serious nervous system sequelae.With the technical improvement of molecular genetics,there have been many progresses in the study of genetic diagnosis,genotype-phenotype correlation and gene therapy of hyperphenylalaninemia.This article reviews the history and classification of hyperphenylalaninemia,the characteristics of gene mutation,the methods of genetic diagnosis,the genotype-phenotype correlation,and the progress of new therapy.

Newborn Screening for Phenylketonuria: Latin American Consensus Guidelines

Abstract Newborn screening (NBS) for phenylketonuria in Latin America gave its first step in an organized way 3 decades ago when the first national NBS program was implemented in Cuba. From then onward, it experienced a slow but continuous growing, being currently possible to find from countries where no NBS activity is known to several countries with consolidated NBS programs. This complex scenario gave rise to a great diversity in the criteria used for sample collection, selection of analytical methods, and definition of cutoff values. Considering this context, a consensus meeting was held in order to unify such criteria, focusing the discussion in the following aspects—recommended blood specimens and sample collection time; influence of early discharge, fasting, parenteral nutrition, blood transfusions, extracorporeal life support, and antibiotics; main causes of transient hyperphenylalaninemias; required characteristics for methods used in phenylalanine measurement; and finally, criteria to define the more appropriate cutoff values.

Paying more attention to the prevention and treatment of maternal phenylketonuria / 中华实用儿科临床杂志

Since 1981,neonatal screening of hyperphenylalaninemia(HPA) has been carrying on in China.The newborns with phenylketonuria(PKU) have been good growthing and developing.Some of them already take part in the marriage period.The fetal brain developmental disorders and various teratogenesis could be leaded if the pregnant women with PKU have high blood concentration of phenylalaninine,namely,maternal PKU syndrome would happen.Now,the international latest progress,including mechanism,prevention,tetrahydrobiopterin support treatment of maternal PKU and the comprehensive management for adult female patients with PKU were summarized,and would like to provide some references for preventing the occurrence of maternal PKU syndrome.

Clinical characteristics and intervention in maternal phenylketonuria / 中国小儿急救医学

Maternal phenylketonuria(MPKU) is a syndrome caused by high phenylalanine concentrations in serum of pregnant women with phenylketonuria.MPKU results in neonatal microcephaly,facial dysmorphism,congenital heart defects,mental retardation,intrauterine growth restriction,behavior and emotional problems.To control serum Phe level of pregnant phenylketonuria women and maintain Phe concentration between 120 to 360μmol/L will prevent offspring poor outcomes such as intellectual disabilities and microcephaly.Three level interventions are best ways in MPKU management.

The proportion of tetrahydrobiopterin deficiency and PAH gene deficiency variants among cases with hyperphenyalaninemia in Western Iran.

BACKGROUND: Defects either in phenylalanine hydroxylase (PheOH) or in the production and recycling of its cofactor (tetrahydrobiopterin [BH4]) are the causes of primary hyperphenylalaninemia (HPA). The aim of our study was to investigate the current status of different variants of HPA Kurdish patients in Kermanshah province, Iran. MATERIALS AND METHODS: From 33 cases enrolled in our study, 32 were identified as HPA patients. Reassessing of pre‑treatment phenylalanine concentrations and the analysis of urinary pterins was done by high‑performance liquid chromatography method. RESULTS: A total of 30 patients showed PAH deficiency and two patients were diagnosed with BH4 deficiency (BH4/ HPA ratio = 6.25%). Both of these two BH4‑deficient patients were assigned to severe variant of dihydropteridine reductase (DHPR) deficiency. More than 75% of patients with PAH deficiency classified as classic phenylketonuria (PKU) according their levels of pre‑treatment phenylalanine concentrations. CONCLUSION: Based on the performed study, we think that the frequency of milder forms of PKU is higher than those was estimated before and/or our findings here. Furthermore, the frequency of DHPR deficiency seems to be relatively high in our province. Since the clinical symptoms of DHPR deficiency are confusingly similar to that of classic PKU and its prognosis are much worse than classical PKU and cannot be solely treated with the PKU regime, our pilot study support that it is crucial to set up screening for BH4 deficiency, along with PAH deficiency, among all HPA patients diagnosed with HPA.

Triagem neonatal para hiperfenilalaninemia: um estudo de coorte / Newborn screening for hyperphenylalaninemia: a cohort study

Introdução: A Fenilcetonúria Clássica é causada pela deficiência da enzima hepática fenilalaninahidroxilase. Se não diagnosticada e tratada precocemente, causa retardo mental. O objetivo deste estudo foi identificar indivíduos submetidos à triagem neonatal no Rio Grande do Sul entre 1986 e 2003, com teste positivo para hiperfenilalaninemia, estimar a prevalência de hiperfenilalaninemias, verificar níveis de controle e correlacionar os anos de realização do teste, início do tratamento, evolução e quadro clínico. Métodos: Casos de hiperfenilalaninemia foram identificados nos laboratórios e clínicas de tratamento. Foi aplicado questionário, contendo variáveis demográficas e sobre a patologia, o desenvolvimento infantil, a escolaridade, o aconselhamento genético e o rastreamento neonatal. Foram avaliados pacientes entre 6 meses e 16 anos de idade. Na análise estatística, utilizou-se o teste do qui-quadrado e ANOVA para avaliar a associação entre ano do diagnóstico e controle de fenilalanina e regressão logística para avaliar o efeito conjunto de idade do diagnóstico e controle de fenilalanina sobre o atraso no desenvolvimento. Resultados: De 1986 a 2003, 418 crianças apresentaram teste positivo para fenilalanina. Destes, 351 (84,0%) apresentaram resultados normais na segunda amostra, 58 (13,9%) foram considerados portadores de hiperfenilalaninemia e 9 (2,1%) tiveram o seguimento perdido. A cobertura do programa foi de 50%. Sobre o aconselhamento genético, 39 entrevistados (72,2%) responderam não saber, não lembrar ou deram respostas incorretas. Conclusão: Não se observou tendência histórica do diagnóstico ter se tornado mais precoce ou do controle laboratorial ter se tornado melhor. O controle bioquímico da fenilalanina não dependeu da precocidade do diagnóstico e sim, da idade dos pacientes.

Introduction: Classical phenylketonuria is caused by deficiency of the hepatic enzyme phenylalanine hydroxylase. If not diagnosed and treated early, it causes mental retardation. The aim of this study was to identify patients who underwent neonatal screening in Rio Grande do Sul between 1986 and 2003 and tested positive for hyperphenylalaninemia, to estimate the prevalence of hyperphenyl-alaninaemias, to check the levels of control, and to correlate the years of testing, initiation of treatment, evolution and clinical picture. Methods: Cases of hyperphenylalaninemia were identified in laboratories and treatment clinics. A questionnaire was administered containing demographic variables and about the pathology, child development, education, genetic counseling and neonatal screening. We evaluated patients between 6 months and 16 years of age. The statistical analysis used the chi-square test and ANOVA to assess the association between year of diagnosis and control of phenylalanine and logistic regression to assess the combined effect of age at diagnosis and control of phenylalanine on the developmental delay. Results: From 1986 to 2003, 418 children tested positive for phenylalanine. Of these, 351 (84.0%) had normal results in the second sample, 58 (13.9%) were considered with hyperphenylalaninemia, and 9 (2.1%) were lost for follow-up . The coverage of the program was 50%. Concerning genetic counseling, 39 respondents (72.2%) reported not knowing, not remembering or gave incorrect answers. Conclusion: There was no historical trend of diagnosis having become earlier or of laboratory control having improved. The biochemical control of phenylalanine was dependent on patient age rather than on early diagnosis.

Neonatal Screening for Inborn Errors of Metabolism in Shanghai / 临床儿科杂志

Objectives Inborn errors of metabolism (IEM) has a diverse spectrum and different incidence in different countries, the early diagnosis at presymptomatic stage is imperative to benefic patient from sequelae. Phenylke-tonuria (PKU) / hyperphenylalaninemia (HPA) is the most common metabolism disorder in Shanghai as well as in other regions. The study is to further clarify the incidence of inborn errors of metabolism among newborn in Shanghai. Methods The dried blood spot specimens were collected from near 90 local maternity and children's hospitals or general hospitals in Shanghai. PKU/HPA screening was carried out by fluorometric method. Neonatal screening using tandem mass spectrometry was performed in one of the study centers, Xinhua neonatal screening center. Results A total of 815 160 cases were screened from 2001 - 2007 in Shanghai, the incidence of PKU/HPA was 1 : 12 351. The tetrahydrobiopterin deficiency was 12.9% among hyperphenylalaninemia patients. According to the 116 000 neonatal samples data detected by tandem mass spectrometry, 20 cases were confirmed diagnosis, including 6 kinds diseases, it was PKU/HPA, maple syrup urine disease, methylmalonicacidemia, propionic acidemia, 3-methylcrotonyl-CoA carboxylase defection, and short chain aeyl-CoA dehydrogenase deficiency. Conclusions The pilot study shown that inborn errors of metabolism neonatal screen-ing using tandem mass was 1 : 5 800 in Shanghai, PKU/HPA was the most common disease. It is expected that the expansion of newborn screening using tandem mass spectrometry could be further considered and further improving inborn errors of metabolism preventive services in Shanghai.

Protective Effect of Recombinant Adeno-Associated Virus 2/8-Mediated Gene Therapy from the Maternal Hyperphenylalaninemia in Offsprings of a Mouse Model of Phenylketonuria

Phenylketonuria (PKU) is an autosomal recessively inherited metabolic disorder caused by a deficiency of phenylalanine hydroxylase (PAH). The accumulation of phenylalanine leads to severe mental and psychomotor retardation, and the fetus of an uncontrolled pregnant female patient presents with maternal PKU syndrome. We have reported previously on the cognitive outcome of biochemical and phenotypic reversal of PKU in a mouse model, Pah(enu2), by the AAV serotype 2-mediated gene delivery of a human PAH transgene. However, the therapeutic efficacy had been limited to only male PKU mice. In this study, we generated a pseudotyped recombinant AAV2/8-hPAH vector and infused it into female PKU mice through the hepatic portal vein or tail vein. Two weeks after injection, complete fur color change to black was observed in female PKU, as in males. The PAH activity in the liver increased to 65-70% of the wild-type activity in female PKU mice and to 90% in male PKU mice. Plasma phenylalanine concentration in female PKU mice decreased to the normal value. In addition, the offsprings of the treated female PKU mice can rescue from the harmful effect of maternal hyperphenylalaninemia. These results indicate that recombinant AAV2/8-mediated gene therapy is a potential therapeutic strategy for PKU.

Clinical Phenotype of Different Hyperphenylalaninemia Patients / 实用儿科临床杂志

Objective To explore clinical characteristics of phenylalanine hydroxylase(PAH) deficiency in differential diagnosis among hyperphenylalaninemia(HPA) patients and compare the responses to diet treatment in HPA patients.Methods Tetrahydrobiopterin(BH4,20 mg/kg) loading test or combined phenylalanine(Phe,100 mg/kg) and BH4 loading test was carried out among 44 HPA patients.The urine pterine profile analysis and dihydropteridine reductase(DHPR) activity in dry blood filter spot were analyzed simultaneously.Electroencephalogram(EEG) and average full scale development quotient(DQ) were performed in all patients.PAH deficiency patients were given low Phe diet treatment to decrease Phe level for 120-360 ?mol/L and followed up their Phe tolerance.Results Twelve BH4 responsive PAH deficiency patients were diagnosed who were 7 males and 5 females,mean age was 7.8 months.Their metabolic phenotype was moderate or mild HPA.Diet control could decrease Phe level among BH4 deficiency patients but not prevent their neural damage and their EEG abnormal rate was higher.BH4 responsive patients had higher DQ than others and their Phe tolerance increased during diet treatment.Conclusions BH4 responsive PAH deficiency patients can obtain better purpose with diet recipe.The differential diagnosis for BH4 deficiency shall be carried out in all patients with HPA as soon as possible.

Expression of two neuron developmental associated genes induced by hyperphenylalanine with real time quantitative RT-PCR / 中华检验医学杂志

Objective To determine the expression of two neuron developmental associated genes induced by hyperphenylalanine.Methods Primary embryonal rat cerebral cortical neurons were cultured for three day and cells induced by hyperphenylalanine for 12 hours.Real time quantitative RT-PCR was used to determine the influence of hyperphenylalanine on the expression of GAP-43 and Go?1 genes.Results GAP-43 mRNA was upregulated to 2.25 times and Go?1 was downregulated to 3.31 times by hyperphenylalanine.Conlusion Hyperphenylalanine may interfere the normal development of cerebral cortical neurons through influencing the expression of GAP-43 and Go?1 genes.

Two Cases of Tetrahydrobiopterin Deficiency

Tetrahydrobiopterin(BH4) deficiency is a rare type of hyperphenylalaninemia and usually leads to a progressive neurologic deterioration despite early dietary control of blood phenylalanine concentration. We experienced two cases of BH4 deficiency in brother and sister, confirmed by biochemical study of blood and urine. They had suffered from a progressive neurologic illness such as mental retardation, severe hypotonia, seizure, and athetotic movements started at 3 months of their age. Blood amino-acid analysis showed mild hyperphenylalaninemia with elevated urinary neopterin, and reduced urinary biopterin. Their neurologic deteriorations were dramatically improved after replacement of BH4 and dopamine agonist.