Enfermedad de pompe: presentación de un caso

Presentamos el caso de una niña de 6 meses de ascendencia china con enfermedad de Pompe diagnosticada a partir de una miocardiopatía hipertrófica biventricular e hipotonía global. En esta enfermedad el acúmulo de glucógeno lisosomal principalmente en el corazón y músculo esquelético ocasiona la mayoría de la sintomatología clínica. En esta paciente la hipotonía generalizada, macroglosia, debilidad en el llanto y la confirmación ecocardiográfica de una miocardiopatía hipertrófica biventricular fueron el punto inicial para la sospecha clínica de la enfermedad que, junto a la elevación de enzimas musculares y hepáticas, condujo al estudio de alfa-glucosidasa ácida (AGA) que confirmó el diagnóstico. Desde 2006 existe terapia de reemplazo enzimático que permite mejorar la sobrevida y la calidad de vida si el diagnóstico se realiza precozmente.We are presenting the case of a 7 month old infant with infantile Pompe disease, who was the first case treated by enzyme replacement therapy (ERT) at our Hospital.The patient was of chinese ancestry and was suspected to have the disease after finding biventricular hypertrophic myocardiopathy and muscle weakness and hypotonia. Other relevant features were macroglosia and increase in CK level as well as the results of the electrophysiology studies. In view of the new possibility of ERT, educational efforts must be done in order to perform early diagnosis before signs of severe cardiorespiratory failure develops, and to improve survival and quality of life of patients with this condition

Phenylalanine Hydroxylase (PAH) Genotyping in PKU Argentine Patients

Phenylketonuria (PKU, OMIM 261600) is predominantly caused by mutations in the PAH gene. One hundred and three Argentine PKU patients were studied by Sanger sequencing; 101 were completely characterized (90.3% were compound heterozygotes). Fifty-four different pathogenic variants were identified. Mutations were distributed all along the PAH gene but concentrated in exon 7 (26%), 12 (12%), 11 (10%), and 6 (10%). 77% were missense, and 77% affected the enzyme catalytic domain, nine mutations accounted for 57% of 179 studied alleles: p.Arg261Gln (Allele frequency(AF):10.6%), c.1066-11G>A (AF:9,5%), p.Arg408Trp (AF:8,3%), p.Tyr414Cys (AF:5,5%), p.Ala403Val, p.Val388Met, and p.Arg158Gln (AF: 5% each), p.Leu48Ser, and p.Ile65Thr (AF:4% each). The predicted phenotype was assigned by Guldberg´s arbitrary value (AV) and compared with the clinical phenotype based in tolerance to Phe intake. 29.1% (n:30) were hyperphenylalaninemias, 18.5% (n:19) mild-PKU, 27.2% (n:28) moderate-PKU and 25.2 % (n:26) classical-PKU. Genotype/phenotype correlation was statistically significant (p<0.001) Overall concordance was 62,5%: 93.3% in hyperphenylalaninemia, 64.7% in mild-PKU and 65.4% in classical patients. The moderate-PKU showed a weak concordance (17%) with milder AV prediction than clinical assessment. 74% of discordant moderate patients harbored p.Arg261Gln, and p.Val388Met. Our cohort is highly heterogeneous, with predominant Mediterranean influence (mainly Spanish), but with differences with other Latin-American countries.Fil: Enacán, Rosa E.. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Miñana, Mariana Nuñez. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Fernandez, Luis. Universidad Autónoma de Madrid; EspañaFil: Valle, María Gabriela. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Salerno, Mercedes. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Fraga, Claudia I.. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Santos Simarro, Fernando. Universidad Autónoma de Madrid; EspañaFil: Prieto, Laura. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Lapunzina, Pablo. Universidad Autónoma de Madrid; EspañaFil: Specola, Norma. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentina. Fundacion de Endocrinologia Infantil.; Argentin

Current practices and challenges in the diagnosis and management of pku in Latin America: A multicenter survey

This study aimed to describe the current practices in the diagnosis and dietary management of phenylketonuria (PKU) in Latin America, as well as the main barriers to treatment. We developed a 44-item online survey aimed at health professionals. After a pilot test, the final version was sent to 25 practitioners working with inborn errors of metabolism (IEM) in 14 countries. Our results include 22 centers in 13 countries. Most countries (12/13) screened newborns for PKU. Phenylalanine (Phe) targets at different ages were very heterogeneous among centers, with greater consistency at the 0–1 year age group (14/22 sought 120–240 µmol/L) and the lowest at >12 years (10 targets reported). Most countries had only unflavored powdered amino acid substitutes (10/13) and did not have low-protein foods (8/13). Only 3/13 countries had regional databases of the Phe content of foods, and only 4/22 centers had nutrient analysis software. The perceived obstacles to treatment were: low purchasing power (62%), limited/insufficient availability of low-protein foods (60%), poor adherence, and lack of technical resources to manage the diet (50% each). We observed a heterogeneous scenario in the dietary management of PKU, and most countries experienced a lack of dietary resources for both patients and health professionals.Fil: Poloni, Soraia. Hospital de Clínicas de Porto Alegre; BrasilFil: Dos Santos, Bruna Bento. Universidade Federal do Rio Grande do Sul; Brasil. Hospital de Clínicas de Porto Alegre; BrasilFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Specola, Norma. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Pereyra, Marcela. Gobierno de la Provincia de Mendoza. Hospital Pediátrico Humberto Notti; ArgentinaFil: Saborío Rocafort, Manuel. Universidad de Costa Rica; Costa RicaFil: Salazar, María Florencia. Universidad de Chile; ChileFil: Leal-Witt, María Jesús. Universidad de Chile; ChileFil: Castro, Gabriela. Universidad de Chile; ChileFil: Peñaloza, Felipe. Universidad de Chile; ChileFil: Wong, Sunling Palma. Hospital Nacional de Niños; Costa RicaFil: Badilla Porras, Ramsés. Hospital Nacional de Niños; Costa RicaFil: Ortiz Paranza, Lourdes. Ministerio de Salud Pública y Bienestar Social; ParaguayFil: Sanabria, Marta Cristina. Hospital de Clínicas; ParaguayFil: Vela Amieva, Marcela. Instituto Nacional de Pediatría; MéxicoFil: Morales, Marco. No especifíca;Fil: Caro Naranjo, Amanda Rocío. Pontificia Universidad Javeriana; ColombiaFil: Mahfoud, Antonieta. Pontificia Universidad Javeriana; ColombiaFil: Colmenares, Ana Rosa. Hospital Clinica Caracas-Materno Infantil de Caricuao; VenezuelaFil: Lemes, Aida. Instituto de Seguridad Social; UruguayFil: Sotillo Lindo, José Fernando. Hospital de especialidades Pediátricas “Omar Torrijos Herrera"; PanamáFil: Perez, Ceila. Robert Reid Cabral Children’s Hospital; República DominicanaFil: Martínez Rey, Laritza. Centro Nacional de Genética Médica; CubaFil: Zayas Torriente, Georgina María. Centro de Nutrición e Higiene de los Alimentos del Instituto Nacional de Higiene, Epidemiología y Microbiología; CubaFil: Farret Refosco, Lilia. Hospital de Clínicas de Porto Alegre; BrasilFil: Doederlein Schwartz, Ida Vanessa. Universidade Federal do Rio Grande do Sul; Brasil. Hospital de Clínicas de Porto Alegre; BrasilFil: Cornejo, Veronica. Universidad de Chile; Chil

The Genetic Landscape and Epidemiology of Phenylketonuria

Phenylketonuria (PKU), caused by variants in the phenylalanine hydroxylase (PAH) gene, is the most common autosomal-recessive Mendelian phenotype of amino acid metabolism. We estimated that globally 0.45 million individuals have PKU, with global prevalence 1:23,930 live births (range 1:4,500 [Italy]-1:125,000 [Japan]). Comparing genotypes and metabolic phenotypes from 16,092 affected subjects revealed differences in disease severity in 51 countries from 17 world regions, with the global phenotype distribution of 62% classic PKU, 22% mild PKU, and 16% mild hyperphenylalaninemia. A gradient in genotype and phenotype distribution exists across Europe, from classic PKU in the east to mild PKU in the southwest and mild hyperphenylalaninemia in the south. The c.1241A gt G (p.Tyr414Cys)-associated genotype can be traced from Northern to Western Europe, from Sweden via Norway, to Denmark, to the Netherlands. The frequency of classic PKU increases from Europe (56%) via Middle East (71%) to Australia (80%). Of 758 PAH variants, c.1222C gt T (p.Arg408Trp) (22.2%), c.1066-11G gt A (IVS10-11G gt A) (6.4%), and c.782G gt A (p.Arg261Gln) (5.5%) were most common and responsible for two prevalent genotypes: p.[Arg408Trp];[Arg408Trp] (11.4%) and c.[1066-11G gt A];[1066-11G gt A] (2.6%). Most genotypes (73%) were compound heterozygous, 27% were homozygous, and 55% of 3,659 different genotypes occurred in only a single individual. PAH variants were scored using an allelic phenotype value and correlated with pre-treatment blood phenylalanine concentrations (n = 6,115) and tetrahydrobiopterin loading test results (n = 4,381), enabling prediction of both a genotype-based phenotype (88%) and tetrahydrobiopterin responsiveness (83%). This study shows that large genotype databases enable accurate phenotype prediction, allowing appropriate targeting of therapies to optimize clinical outcome

Neuropathology of phenylketonuria (PKU)

Untreated phenylketonuria (PKU) causes cognitive, neuropsychological and motor skills impairment as well as microcephaly and demyelization. Persistent hyperphenylalaninemia produces toxicity on neurons and glial cells, alters cortical development, growth and dendritic density High levels of phenylalanine and low levels of neutral aminoacids in the brain disrupt neurotransmitter synthesis, increase oxidative damage, reduce the number of dopaminergic neurons and decrease the length of dendrites. White matter lesions are not present in all patients and there is no relation between these lesions and clinical severity. It has been shown that selenium and carnitine supplementation can decrease lipid and protein peroxidation. There are several mechanisms involved in neurodegeneration of patients with phenylketonuria; early treatment and strict nutritional control significantly improve the prognosis of these patients

Aromatic l-aminoacid decarboxylase deficiency: unusual neonatal presentation and additional findings in organic acid analysis

Aromatic l-aminoacid decarboxylase (AADC) deficiency is a neurotransmitter defect leading to a combined deficiency of catecholamines and serotonin. Patients are usually detected in infancy due to developmental delay, hypotonia, and extrapyramidal movements. Diagnosis is based on an abnormal neurotransmitter metabolite profile in CSF and reduced AADC activity in plasma. An elevation of vanillactic acid (VLA) has been described as the only abnormality detected in organic acid analysis (OA) of urine. We report a patient who presented in the neonatal period with lethargy, hypotonia, metabolic acidosis, and hypoglycemia. Blood ammonia, lactic acid, and acylcarnitines were normal, but OA of a urine sample showed a small increase of VLA, raising the suspicion of AADC deficiency. The patient was lost to follow-up until the age of 8 months, when he presented with dystonia, abnormal movements, oculogyric crises, and hypothermia. Repeat OA showed not only increased levels of VLA, but also increased vanilpyruvic acid (VPA), N-acetyl-vanilalanine (AVA) and N-acetyl-tyrosine (NAT). Neurotransmitter analysis in CSF showed increased vanilalanine (1200 nmol/L, ref <100) with decreased levels of 5-hydroxy-indoleacetic acid (5-HIAA, < 5 nmol/L; ref 152-462), homovanillic acid (HVA, 83 nmol/L; ref 302-845), and methoxy-hydroxy-phenyl-glycol ( <5 nmol/L; ref 51-112). AADC activity in plasma was nearly undetectable. In the urine, low excretion of vanilmandelic acid ( <0.3 micromol/mmol creat; ref 0.3-20) and 5-HIAA (0.9 micromol/mmol creat; ref 4-18), was found, but HVA was normal and dopamine even elevated. This contradictory phenomenon of hyperdopaminuria has been described earlier in AADC deficient patients. We postulate that VPA and AVA could originate from vanilalanine (through a transaminase and an acetylase respectively), while NAT could originate from tyrosine through an AA acetylase. This report expands the clinical presentation of AADC deficiency and adds new markers of the disease for OA analysis, improving detection of AADC deficient patients in general metabolic screening procedure

Argentinian clinical genomics in a leukodystrophies and genetic leukoencephalopathies cohort: Diagnostic yield in our first 9 years

Introduction and objectives: Leukodystrophies and genetic leukoencephalopathies constitute a vast group of pathologies of the cerebral white matter. The large number of etiopathogenic genes and the frequent unspecificity on the clinical-radiological presentation generate remarkable difficulties in the diagnosis approach. Despite recent and significant developments, molecular diagnostic yield is still less than 50%. Our objective was to develop and explore the usefulness of a new diagnostic procedure using standardized molecular diagnostic tools, and next-generation sequencing techniques. Materials and methods: A prospective, observational, analytical study was conducted in a cohort of 46 patients, evaluated between May 2008 and December 2016, with a suspected genetic leukoencephalopathy or leukodystrophy. A diagnostic procedure was set up using classical monogenic tools in patients with characteristic phenotypes, and next-generation techniques in nonspecific ones. Results: Global diagnostic procedure yield was 57.9%, identifying the etiological pathogenesis in 22 of the 38 studied subjects. Analysis by subgroups, Sanger method, and next-generation sequencing showed a yield of 64%, and 46.1% respectively. The most common pathologies were adrenoleukodystrophy, cerebral autosomal-dominant arteriopathy with subcortical infarcts (CADASIL), and vanishing white matter disease. Conclusions: Our results confirm the usefulness of the proposed diagnostic procedure expressed in a high diagnostic yield and suggest a more optimal cost-effectiveness in an etiological analysis phase.Fil: Cohen, Leila. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Manín, Analisa. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Medina, Nancy. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Rodríguez Quiroga, Sergio. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: González Morón, Dolores. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Rosales, Julieta. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Amartino, Hernan. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Specola, Norma. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Córdoba, Marta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Kauffman, Marcelo Andres. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Vega, Patricia. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; Argentin

Argentinian clinical genomics in a leukodystrophies and genetic leukoencephalopathies cohort: Diagnostic yield in our first 9 years

Introduction and objectives: Leukodystrophies and genetic leukoencephalopathies constitute a vast group of pathologies of the cerebral white matter. The large number of etiopathogenic genes and the frequent unspecificity on the clinical-radiological presentation generate remarkable difficulties in the diagnosis approach. Despite recent and significant developments, molecular diagnostic yield is still less than 50%. Our objective was to develop and explore the usefulness of a new diagnostic procedure using standardized molecular diagnostic tools, and next-generation sequencing techniques. Materials and methods: A prospective, observational, analytical study was conducted in a cohort of 46 patients, evaluated between May 2008 and December 2016, with a suspected genetic leukoencephalopathy or leukodystrophy. A diagnostic procedure was set up using classical monogenic tools in patients with characteristic phenotypes, and next-generation techniques in nonspecific ones. Results: Global diagnostic procedure yield was 57.9%, identifying the etiological pathogenesis in 22 of the 38 studied subjects. Analysis by subgroups, Sanger method, and next-generation sequencing showed a yield of 64%, and 46.1% respectively. The most common pathologies were adrenoleukodystrophy, cerebral autosomal-dominant arteriopathy with subcortical infarcts (CADASIL), and vanishing white matter disease. Conclusions: Our results confirm the usefulness of the proposed diagnostic procedure expressed in a high diagnostic yield and suggest a more optimal cost-effectiveness in an etiological analysis phase.Fil: Cohen, Leila. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Manín, Analisa. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Medina, Nancy. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Rodríguez Quiroga, Sergio. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: González Morón, Dolores. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Rosales, Julieta. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Amartino, Hernan. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Specola, Norma. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Córdoba, Marta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Kauffman, Marcelo Andres. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; ArgentinaFil: Vega, Patricia. Universidad de Buenos Aires. Facultad de Medicina. Centro Universitario de Neurología "Dr. José María Ramos Mejía".; Argentin

Improving the diagnosis of cobalamin and related defects by genomic analysis, plus functional and structural assessment of novel variants

Abstract Background Cellular cobalamin defects are a locus and allelic heterogeneous disorder. The gold standard for coming to genetic diagnoses of cobalamin defects has for some time been gene-by-gene Sanger sequencing of individual DNA fragments. Enzymatic and cellular methods are employed before such sequencing to help in the selection of the gene defects to be sought, but this is time-consuming and laborious. Furthermore some cases remain undiagnosed because no biochemical methods have been available to test for cobalamin absorption and transport defects. Results This paper reports the use of massive parallel sequencing of DNA (exome analysis) for the accurate and rapid genetic diagnosis of cobalamin-related defects in a cohort of affected patients. The method was first validated in an initial cohort with different cobalamin defects. Mendelian segregation, the frequency of mutations, and the comprehensive structural and functional analysis of gene variants, identified disease-causing mutations in 12 genes involved in the absorption and synthesis of active cofactors of vitamin B12 (22 cases), and in the non-cobalamin metabolism-related genes ACSF3 (in four biochemically misdiagnosed patients) and SUCLA2 (in one patient with an unusual presentation). We have identified thirteen new variants all classified as pathogenic according to the ACGM recommendation but four were classified as variant likely pathogenic in MUT and SUCLA2. Functional and structural analysis provided evidences to classify them as pathogenic variants. Conclusions The present findings suggest that the technology used is sufficiently sensitive and specific, and the results it provides sufficiently reproducible, to recommend its use as a second-tier test after the biochemical detection of cobalamin disorder markers in the first days of life. However, for accurate diagnoses to be made, biochemical and functional tests that allow comprehensive clinical phenotyping are also needed

Additional file 3: of Improving the diagnosis of cobalamin and related defects by genomic analysis, plus functional and structural assessment of novel variants

Horizontal and vertical coverages of cobalamin and related genes. (DOCX 24 kb