New data supporting that early diagnosis and treatment are possible and necessary in intracellular cobalamin depletion: the case of transcobalamin II deficiency.

OBJECTIVES: Transcobalamin II (TC) promotes the cellular uptake of cobalamin (Cbl) through receptor-mediated endocytosis of the TC-cbl complex in peripheral tissues. TC deficiency is a rare disorder that causes intracellular Cbl depletion. It presents in early infancy with a failure to thrive, diarrhea, anemia, agammaglobulinemia, and pancytopenia. Data from five TC-deficient patients including clinical, biochemical, and molecular findings, as well as long-term outcomes, were collected. CASE PRESENTATION: Mutation analysis revealed one unreported pathogenic variant in the TCN2 gene. One patient had exocrine pancreatic insufficiency. We conducted a retrospective analysis of C3 and C3/C2 from dried blood samples, as this is implemented for newborn screening (NBS). We detected a marked increase in the C3/C2 ratio in two samples. Treatment was based on parenteral Cbl. Three patients treated before six months of age had an initial favorable outcome, whereas the two treated later or inadequately had neurological impairment. CONCLUSIONS: This is the first report of Argentinean patients with TC deficiency that detected a new variant in TCN2. NBS may be a tool for the early detection of TC deficiency. This data emphasizes that TC deficiency is a severe disorder that requires early detection and long-term, aggressive therapy. Accurate diagnosis is imperative, because early detection and treatment can be life-saving.

Adherence to PKU guidelines among patients with phenylketonuria: A cross-sectional national multicenter survey-based study in Argentina, Brazil, and Mexico.

Objective: To characterize adherence to Phenylketonuria (PKU) management practices among PKU patients treated at reference sites around Argentina, Brazil, and Mexico. Methods: This is a retrospective, observational, multicenter, and multinational survey-based study using aggregate data. From an initial list of 40 sites, 22 clinicians expressed interest in completing the survey, with 20 clinicians from 20 unique sites fulfilling all the study criteria. The Survey contained 28 questions, including respondent's clinic characteristics, clinic PKU treatment recommendations, and patient adherence to clinic recommendations. Survey was available in local languages, and the respondents were asked to consult their clinic records to complete their responses. Adherence was assessed by target blood phenylalanine (Phe), target blood testing frequency, and clinic visits. Results: A total of 1077 (out of 1377) actively managed PKU patients (seen in the clinic in the last 3 years) from 13 clinics in Brazil, six in Argentina, and one in Mexico were analyzed. Upper blood Phe target was set over 360 µMol/L in 70% of the clinics for adult patients. Around 40% of the patients >30 years old had Phe blood tests done twice a year or less, with 60% of the clinics recommending semestral visits for adults <30 years old. Twice a month was the most common frequency of visits for <1 year old. The COVID-19 pandemic was a disruptor for frequency of visits and exams. Conclusions: These results show that there is still room for improvement in terms of adherence, namely in adults and older children. More efforts must be made to educate patients and healthcare professionals about the importance of treatment adherence, accompanied by public policies that expand access to pharmacological and dietary treatment with diversity and quality to improve adherence to adequate blood Phe levels.

CONSENSO ARGENTINO SOBRE LA TRANSICIÓN DE LOS CUIDADOS PEDIÁTRICOS A LOS CUIDADOS ADULTOS EN PACIENTES CON ENFERMEDADES CONGÉNITAS DEL METABOLISMO / CONSENSUS STATEMENT ON THE TRANSITION FROM PEDIATRIC CARE TO ADULT CARE IN PATIENTS WITH INBORN ERRORS OF METABOLISM IN ARGENTINA

Introducción: Los errores congénitos del metabolismo (ECM) son enfermedades producidas por trastornos genéticos que alteran la función de distintas vías metabólicas. La transición desde el sistema de atención médica pediátrica a la de adultos es un proceso clave en el desarrollo evolutivo de las personas con condiciones crónicas de salud. Los servicios de salud presentan fallas en satisfacer las necesidades de los jóvenes y sus familias. El objetivo fue definir un conjunto de herramientas y recomendaciones, adaptadas al contexto local de Argentina, para orientar al equipo de salud en el acompañamiento del proceso de transición de cuidados. Asimismo, se buscó analizar barreras y facilitadores para su implementación. Métodos: se definieron preguntas clínicas que se respondieron con la mejor evidencia científica disponible. Se elaboraron recomendaciones para jóvenes y adolescentes con diagnóstico de ECM que se encuentren en proceso de transición entre el servicio de atención pediátrico al servicio de adultos. Las recomendaciones elaboradas se consensuaron con expertos en la temática a través de un método Delphi. Resultados: se elaboraron y consensuaron 13 recomendaciones que permitirán guiar el proceso de transición de los cuidados pediátricos al de adultos en personas con ECM. Conclusiones: estas recomendaciones ayudarán al equipo de salud a mejorar la calidad de atención de estos pacientes y garantizar que ellos y sus familias tengan una experiencia adecuada durante todo el proceso de transición

Introduction: Inborn errors of metabolism (IEM) are diseases caused by genetic disorders that alter the function of different metabolic pathways. The transition from the pediatric to adult health care system is a key process in the evolutionary development of patients with chronic health conditions. Health services are failing to meet the needs of young patients and their families. The objective was to define a set of tools and recommendations, adapted to the local context of Argentina, to guide the health team in accompanying the process of transition. Likewise, it sought to analyze barriers and facilitators for its implementation. Methods: clinical questions were defined and answered with the best available scientific evidence. Recommendations were developed for young patients and adolescents diagnosed with IEM who are in the process of transitioning from the pediatric care service to the adult service. The recommendations developed were agreed with experts in the field through a Delphi method. Results: 13 recommendations were developed and agreed upon to guide the transition process from pediatric to adult care in people with IEM. Conclusions: These recommendations will help the health team improve the quality of care for these patients and ensure that they and their families have an adequate experience throughout the transition process

Manejo inicial de la hiperamonemia aguda en pediatría / Initial management of acute hyperammonemia in pediatrics

La hiperamonemia constituye una emergencia médica. No existen publicaciones que hagan referencia a la disponibilidad de recursos, insumos y conocimientos necesarios para el manejo inicial de esta por parte del pediatra en nuestro país, pero, según la experiencia de los autores, los recursos necesarios no se encuentran disponibles los 365 días del año en una gran porción de nuestro territorio. Sobre la base de este estado de situación, de una revisión bibliográfica internacional sobre el tema y de la experiencia de los autores, se elaboraron una serie de recomendaciones para el manejo pediátrico inicial de esta emergencia, que tienen como objetivo poder reducir las deficiencias, permitir una sospecha clínica adecuada que lleve a un diagnóstico y tratamiento de emergencia oportunos, con utilización racional de recursos farmacológicos (algunos de ellos de alto costo), para reducir la morbimortalidad que asocia la patología.

Hyperammonemia is a medical emergency. There are no publications regarding the availability of resources, supplies, and knowledge necessary for the initial management of hyperammonemia by pediatricians in Argentina; however, according to the authors' experience, the necessary resources are not available all year round in a large portion of our territory. Based on such state of affairs, an international bibliographic review on this topic and the authors' experience, we developed a series of recommendations for the initial pediatric management of this emergency, with the objective of reducing deficiencies, allowing adequate clinical suspicion leading to a timely diagnosis and emergency management and a rational use of pharmacological resources (some of which are costly) to reduce the morbidity and mortality associated with hyperammonemia.

Initial management of acute hyperammonemia in pediatrics. / Manejo inicial de la hiperamonemia aguda en pediatría.

Hyperammonemia is a medical emergency. There are no publications regarding the availability of resources, supplies, and knowledge necessary for the initial management of hyperammonemia by pediatricians in Argentina; however, according to the authors' experience, the necessary resources are not available all year round in a large portion of our territory. Based on such state of affairs, an international bibliographic review on this topic and the authors' experience, we developed a series of ecommendations for the initial pediatric management of this emergency, with the objective of reducing deficiencies, allowing adequate clinical suspicion leading to a timely diagnosis and emergency management and a rational use of pharmacological resources (some of which are costly) to reduce the morbidity and mortality associated with hyperammonemia.

La hiperamonemia constituye una emergencia médica. No existen publicaciones que hagan referencia a la disponibilidad de recursos, insumos y conocimientos necesarios para el manejo inicial de esta por parte del pediatra en nuestro país, pero, según la experiencia de los autores, los recursos necesarios no se encuentran disponibles los 365 días del año en una gran porción de nuestro territorio. Sobre la base de este estado de situación, de una revisión bibliográfica internacional sobre el tema y de la experiencia de los autores, se elaboraron una serie de recomendaciones para el manejo pediátrico inicial de esta emergencia, que tienen como objetivo poder reducir las deficiencias, permitir una sospecha clínica adecuada que lleve a un diagnóstico y tratamiento de emergencia oportunos, con utilización racional de recursos farmacológicos (algunos de ellos de alto costo), para reducir la morbimortalidad que asocia la patología.

Trastornos adquiridos y congénitos de la deficiencia de vitamina B12 en niños / Acquired and inherited disorders of vitamin B12 deficiency in children

Vitamin B12 is an essential micronutrient for cell growth and the development of the central nervous system. Its deficiency can manifest clinically as megaloblastic anemia, peripheral neuropathy, myelopathy and neuropsychiatric disorders. Early detection and treatment are essential as it can cause irreversible neurological sequelae. Diagnosis is often challenging as it is based on clinical and biochemical features. Clinically, the symptoms are nonspecific and equivocal. Biochemically, there is no gold standard to detect Cobalamin deficiency. The available biomarkers do not have a defined cut-off value or are not sensitive or specific enough. This article exposes the different causes of vitamin B12 deficiency, analyzes the advantages and disadvantages of biochemical markers and, for the first time, proposes an algorithmic diagnosis using biomarkers and therapeutic tests. The ultimate goal is to alert pediatricians to the difficulties of diagnosing vitamin B12 deficiency and strategies are proposed to differentiate between acquired and congenital cobalamin conditions. Finally, the treatment according to the etiology is described in a practical manner, as well as the expected time for improvement of the biochemical parameters.

La vitamina B12 es un micronutriente fundamental para el crecimiento celular y el desarrollo del sistema nervioso central. Su deficiencia puede manifestarse clínicamente como anemia megaloblástica, neuropatía periférica, mielopatía y trastornos neuropsiquiátricos. La detección y el tratamiento tempranos son esenciales, ya que esta deficiencia puede generar secuelas neurológicas irreversibles. El diagnóstico suele ser un desafío, ya que se basa en pilares clínicos y bioquímicos. Clínicamente, los síntomas son inespecíficos y equívocos. Bioquímicamente no existe un gold standard para diagnosticar la deficiencia de cobalamina. Los biomarcadores existentes no presentan un valor de corte definido o no son lo suficientemente sensibles o específicos. Este trabajo expone las diferentes causas de deficiencia de vitamina B12, analiza las ventajas y desventajas de los marcadores bioquímicos y por primera vez se plantea un algoritmo diagnóstico mediante biomarcadores y pruebas terapéuticas. El objetivo último es alertar a los pediatras acerca las dificultades que representa el diagnóstico de deficiencia de vitamina B12 y se proponen estrategias para diferenciar cuadros adquiridos versus congénitos de la deficiencia de cobalamina. Por último, se describe de manera práctica el tratamiento según la etiología así como el tiempo esperado para la mejoría de los parámetros bioquímicos.

Efficacy and safety of empagliflozin in glycogen storage disease type Ib: Data from an international questionnaire.

PURPOSE: This paper aims to report collective information on safety and efficacy of empagliflozin drug repurposing in individuals with glycogen storage disease type Ib (GSD Ib). METHODS: This is an international retrospective questionnaire study on the safety and efficacy of empagliflozin use for management of neutropenia/neutrophil dysfunction in patients with GSD Ib, conducted among the respective health care providers from 24 countries across the globe. RESULTS: Clinical data from 112 individuals with GSD Ib were evaluated, representing a total of 94 treatment years. The median age at start of empagliflozin treatment was 10.5 years (range = 0-38 years). Empagliflozin showed positive effects on all neutrophil dysfunction-related symptoms, including oral and urogenital mucosal lesions, recurrent infections, skin abscesses, inflammatory bowel disease, and anemia. Before initiating empagliflozin, most patients with GSD Ib were on G-CSF (94/112; 84%). At the time of the survey, 49 of 89 (55%) patients previously treated with G-CSF had completely stopped G-CSF, and another 15 (17%) were able to reduce the dose. The most common adverse event during empagliflozin treatment was hypoglycemia, occurring in 18% of individuals. CONCLUSION: Empagliflozin has a favorable effect on neutropenia/neutrophil dysfunction-related symptoms and safety profile in individuals with GSD Ib.

Molecular and functional study of pediatric patients with Niemann-Pick C in Argentina / Estudio molecular y funcional de pacientes pediátricos con Niemann-Pick C en Argentina

Abstract Niemann-Pick type C (NP-C) is a rare, autosomal recessive disorder. At least 95% of all the cases with this disease are due to mutations in the NPC1 gene. The clinical signs and symptoms of NP-C are classified into visceral, neurological and psychiatric. Our aim is to report the clinical findings, molecular results and filipin staining of 4 patients. The age of onset, expressed as median and range, was 0.2 (0.08-4.0) years and the age of diagnosis was 4.0 (2.5-8.9) years. Neurological and/or visceral manifestations were presented in our patients. Foamy cells in bone marrow biopsy were found in two patients. Through a molecular analysis of NPC1 gene, one non-reported (novel) and 4 previously described mutations were found. The filipin staining showed a positive pattern in all the patients. The diagnostic confirmation of these pediatric patients means a contribution to the casuistry of this disease in Argentina.

Resumen Niemann-Pick tipo C (NP-C) es una enfermedad poco frecuente, con un patrón de herencia au tosómico recesivo. Al menos el 95% de los casos se producen por mutaciones en el gen NPC1. Los signos y síntomas clínicos de NP-C se clasifican en viscerales, neurológicos y psiquiátricos. En este trabajo presentamos los hallazgos clínicos, los resultados moleculares y la tinción con filipina de 4 pacientes con NP-C. La edad de presentación de los primeros síntomas, expresada como mediana y rango, fue de 0.2 años (0.08-4.0) años y la edad del diagnóstico fue 4.0 (2.5-8.9) años. Los pacientes presentaron manifestaciones neurológicas y / o vis cerales. Se encontraron células espumosas en la biopsia de médula ósea en 2 pacientes. El análisis molecular del gen NPC1 encontró 1 variante nueva y 4 previamente publicadas. La tinción de filipina mostró un patrón positivo en todos los pacientes. La confirmación diagnóstica de este grupo de pacientes pediátricos significa un aporte a la casuística de esta enfermedad en Argentina.

Molecular and functional study of pediatric patients with Niemann-Pick C in Argentina.

Niemann-Pick type C (NP-C) is a rare, autosomal recessive disorder. At least 95% of all the cases with this disease are due to mutations in the NPC1 gene. The clinical signs and symptoms of NP-C are classified into visceral, neurological and psychiatric. Our aim is to report the clinical findings, molecular results and filipin staining of 4 patients. The age of onset, expressed as median and range, was 0.2 (0.08-4.0) years and the age of diagnosis was 4.0 (2.5-8.9) years. Neurological and/or visceral manifestations were presented in our patients. Foamy cells in bone marrow biopsy were found in two patients. Through a molecular analysis of NPC1 gene, one non-reported (novel) and 4 previously described mutations were found. The filipin staining showed a positive pattern in all the patients. The diagnostic confirmation of these pediatric patients means a contribution to the casuistry of this disease in Argentina.

Niemann-Pick tipo C (NP-C) es una enfermedad poco frecuente, con un patrón de herencia autosómico recesivo. Al menos el 95% de los casos se producen por mutaciones en el gen NPC1. Los signos y síntomas clínicos de NP-C se clasifican en viscerales, neurológicos y psiquiátricos. En este trabajo presentamos los hallazgos clínicos, los resultados moleculares y la tinción con filipina de 4 pacientes con NP-C. La edad de presentación de los primeros síntomas, expresada como mediana y rango, fue de 0.2 años (0.08-4.0) años y la edad del diagnóstico fue 4.0 (2.5-8.9) años. Los pacientes presentaron manifestaciones neurológicas y / o viscerales. Se encontraron células espumosas en la biopsia de médula ósea en 2 pacientes. El análisis molecular del gen NPC1 encontró 1 variante nueva y 4 previamente publicadas. La tinción de filipina mostró un patrón positivo en todos los pacientes. La confirmación diagnóstica de este grupo de pacientes pediátricos significa un aporte a la casuística de esta enfermedad en Argentina.

Algunos desafíos en mucopolisacaridosis tipo I / A few challenges in mucopolysaccharidosis type I

Se describen como desafíos actuales en mucopolisacaridosis I la necesidad de una clasificación adecuada, vinculándola a las indicaciones terapéuticas; el diagnóstico temprano desde la pesquisa neonatal, sus ventajas y dificultades hasta la sospecha clínica de las formas grave y atenuada; el cuidado de la patología espinal y oftalmológica, desde el diagnóstico, el seguimiento y el tratamiento; las reacciones alérgicas por terapia de reemplazo enzimático, su diagnóstico y tratamiento. Por último, la transición hacia el cuidado adulto

Here we describe the current challenges of mucopolysaccharidosis type I: the need for an adequate classification, establishing its relationship to therapeutic indications; an early diagnosis, from neonatal screening, its advantages and barriers, to clinical suspicion of severe and attenuated forms; spinal and eye disease care, from diagnosis to follow-up and treatment; allergic reactions caused by enzyme replacement therapy, their diagnosis and treatment. And lastly, transition to adult care

A few challenges in mucopolysaccharidosis type I. / Algunos desafíos en mucopolisacaridosis tipo I.

Here we describe the current challenges of mucopolysaccharidosis type I: the need for an adequate classification, establishing its relationship to therapeutic indications; an early diagnosis, from neonatal screening, its advantages and barriers, to clinical suspicion of severe and attenuated forms; spinal and eye disease care, from diagnosis to follow-up and treatment; allergic reactions caused by enzyme replacement therapy, their diagnosis and treatment. And lastly, transition to adult care.

Se describen como desafíos actuales en mucopolisacaridosis I la necesidad de una clasificación adecuada, vinculándola a las indicaciones terapéuticas; el diagnóstico temprano desde la pesquisa neonatal, sus ventajas y dificultades hasta la sospecha clínica de las formas grave y atenuada; el cuidado de la patología espinal y oftalmológica, desde el diagnóstico, el seguimiento y el tratamiento; las reacciones alérgicas por terapia de reemplazo enzimático, su diagnóstico y tratamiento. Por último, la transición hacia el cuidado adulto.

Nuevas recomendaciones para el cuidado de los pacientes con mucopolisacaridosis tipo I / New recommendations for the care of patients with mucopolysaccharidosis type I

Dados los avances sobre mucopolisacaridosis Icon posterioridad al consenso publicado en la Argentina por un grupo de expertos en 2008, se revisan recomendaciones respecto a estudios genéticos, seguimiento cardiológico, cuidado de la vía aérea, alertas sobre aspectos auditivos, de la patología espinal y neurológica. Se hace revisión de la terapéutica actual y se enfatiza en la necesidad de un diagnóstico y tratamiento precoces, así como de un seguimiento interdisciplinario

Considering the advances made on mucopolysaccharidosis type I after the consensus study published by a group of experts in Argentina in 2008, recommendations about genetic testing, cardiological follow-up, airway care, hearing impairment detection, spinal and neurological conditions, as well as current treatments, were reviewed. Emphasis was placed on the need for early diagnosis and treatment, as well as an interdisciplinary follow-up

Clinical and molecular characterization of mitochondrial DNA disorders in a group of Argentinian pediatric patients.

OBJECTIVE: To describe the clinical and molecular features of a group of Argentinian pediatric patients with mitochondrial DNA (mtDNA) disorders, and to evaluate the results of the implementation of a classical approach for the molecular diagnosis of mitochondrial diseases. METHODS: Clinical data from 27 patients with confirmed mtDNA pathogenic variants were obtained from a database of 89 patients with suspected mitochondrial disease, registered from 2014 to 2020. Clinical data, biochemical analysis, neuroimaging findings, muscle biopsy and molecular studies were analyzed. RESULTS: Patients were 18 females and 9 males, with ages at onset ranging from 1 week to 14 years (median = 4 years). The clinical phenotypes were: mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome (n = 11), Leigh syndrome (n = 5), Kearns-Sayre syndrome (n = 3), Chronic Progressive External Ophthalmoplegia (n = 2), Leber hereditary optic neuropathy (n = 2), myoclonic epilepsy associated with ragged-red fibers (n = 1) and reversible infantile myopathy with cytochrome-C oxidase deficiency (n = 3). Most of the patients harbored pathogenic single nucleotide variants, mainly involving mt-tRNA genes, such as MT-TL1, MT-TE and MT-TK. Other point variants were found in complex I subunits, like MT-ND6, MT-ND4, MT-ND5; or in MT-ATP6. The m.13513G > A variant in MT-ND5 and the m.9185 T > C variant in MT-ATP6 were apparently de novo. The rest of the patients presented large scale-rearrangements, either the "common" deletion or a larger deletion. CONCLUSIONS: This study highlights the clinical and genetic heterogeneity of pediatric mtDNA disorders. All the cases presented with classical phenotypes, being MELAS the most frequent. Applying classical molecular methods, it was possible to achieve a genetic diagnosis in 30% of the cases, suggesting that this is an effective first approach, especially for those centers from low-middle income countries, leaving NGS studies for those patients with inconclusive results.

New recommendations for the care of patients with mucopolysaccharidosis type I. / Nuevas recomendaciones para el cuidado de los pacientes con mucopolisacaridosis tipo I.

Considering the advances made on mucopolysaccharidosis type I after the consensus study published by a group of experts in Argentina in 2008, recommendations about genetic testing, cardiological follow-up, airway care, hearing impairment detection, spinal and neurological conditions, as well as current treatments, were reviewed. Emphasis was placed on the need for early diagnosis and treatment, as well as an interdisciplinary follow-up.

Dados los avances sobre mucopolisacaridosis I con posterioridad al consenso publicado en la Argentina por un grupo de expertos en 2008, se revisan recomendaciones respecto a estudios genéticos, seguimiento cardiológico, cuidado de la vía aérea, alertas sobre aspectos auditivos, de la patología espinal y neurológica. Se hace revisión de la terapéutica actual y se enfatiza en la necesidad de un diagnóstico y tratamiento precoces, así como de un seguimiento interdisciplinario.

Acute liver dysfunction with delayed peak of serum aminotransferase levels as a presentation of ornithine transcarbamylase deficiency in females.

We describe 10 females with ornithine transcarbamylase (OTC) deficiency and liver dysfunction, revealing a unique pattern of hepatocyte injury in which initial hyperammonemia and coagulopathy is followed by a delayed peak in aminotransferase levels. None of the patients required urgent liver transplantation, though five eventually underwent transplant for recurrent metabolic crises. We intend that this novel observation will initiate further investigations into the pathophysiology of liver dysfunction in OTC-deficient patients, and ultimately lead to the development of therapies and prevent the need for liver transplant.

Clinical, Biochemical and Molecular Characterization of a Cohort of Glycogen Storage Disease Type I Patients in a High Complexity Hospital in Argentina

Abstract Glycogen storage disease type I is an autosomal recessive disorder of carbohydrate metabolism that manifests mainly by hepatomegaly and hypoglycemia with short fasts. Despite strict therapy, patients present long-term renal and liver complications. Data of 36 patients,29 GSD Ia and 7 Ib from a high complexity Hospital in Argentina was collected retrospectively. Collected data included diagnosis, anthropometric, biochemical parameters, therapy and follow-up. Treatment increased Height SDS (p=0.012). Patients with good adherence to therapy presented better growth parameters (p=0.049). Instead, admissions were detrimental (p =0.031) and were more common in Ib patients (p=0.002). The early appearance of complications (liver adenomas and nephropathy) was related to sustained triglyceride values > 500mg / dl (p=0.009 and 0.046 respectively). With intensive dietary treatment, clinical and biochemical status improves but cannot be completely corrected in most patients. Growth improves with treatment and this is optimized with adequate adherence. We must take into account that with ageing, more complications will develop.

Clinical and Genetic Characterization and Biochemical Correlation at Presentation in 48 Patients Diagnosed with Urea Cycle Disorders at the Hospital Juan P Garrahan, Argentina

Abstract The clinical and biochemical findings in a cohort of 51 patients with urea cycle disorders followed at the Hospital Garrahan, Buenos Aires, Argentina were analyzed at the time of diagnosis (3 female patients were excluded). Of this cohort, 13/48 patients had early-onset (EO), 23/48 had late-onset (LO), and 12/48 had a different presentation because they had a family risk background (FRB) and had been diagnosed since they were born. The most frequent deficiency disorder was OTCD (65%). The initial ammonium value was evaluated, being higher in the EO group, with a statistically significant difference when compared with LO and FRB. 15/48 patients fell into a coma at the time of diagnosis, mean ammonia was 829.54 μmol / L, and 33/48 did not fell into a coma, the mean ammonium was of 159.3 μmol / L (p = 0.001). 15 patients died: 62% EO, 22% LO (p=0.0216), 17% FRB. A molecular study was performed on 35 patients. Patients with EO presentation suffer the most severe forms and still have high morbimortality. On the other hand, LO forms are forms of less severity that are finally diagnosed as a result of one or more acute episodes.

Molecular analysis of GALT gene in Argentinian population: Correlation with enzyme activity and characterization of a novel Duarte-like allele.

BACKGROUND: Classical galactosemia is an autosomal recessive inherited metabolic disorder caused by mutations in the galactose-1-phosphate uridyltransferase (GALT) gene. GALT enzyme deficiency leads to the accumulation of galactose-1-phosphate in various organs, causing hepatic, renal and cerebral impairment. Over 300 mutations have been reported in the GALT gene. The aim of this study was to describe molecular characterization of GALT gene in Argentinian patients with decreased GALT activity, and to correlate molecular results with enzyme activity. METHODS: 37 patients with enzyme activity below 6.3 µmol/h/g Hb (35% of normal value) were included. GALT activity was measured on red blood cells. DNA was extracted from peripheral blood. p.Gln188Arg mutation was studied by PCR-RFLP and, on samples negative or heterozygous, GALT gene was sequenced. In vivo splicing analysis of the GALT gene was performed on RNA extracted from leukocytes of one patient. RESULTS: 14 different sequence variations were identified among 72 unrelated alleles. The two most common disease-causing mutations were p.Gln188Arg (24/72) and p.Lys285Asn (9/72). Three novel mutations were detected. One of them, c.688G>A, caused partial skipping of exon 9 of the GALT gene. Enzyme activity correlated with GALT genotype in 36 of the 37 patients. CONCLUSION: This is the first report of sequence variations in the GALT gene in the Argentinian population. This study highlights the contribution of the molecular analysis to the diagnosis of Galactosemia and reveals c.688G>A as a novel Duarte-like variant, with a high prevalence in our population.

Deficiencia de cobalamina C de inicio temprano: presentación de caso clínico / Early onset cobalamin C deficiency: clinical case presentation

Cobalamin C (CblC) deficiency is an autosomal recessive disorder caused by mutations of the MMACHC gene that results in impaired synthesis of the methylcobalamin and adenosylcobalamin co-factors. This brings an impaired conversion of dietary cobalamin and therefore dysfunction of two key enzymes generating hyperhomocysteinemia, hypometionimemia and methylmalonic aciduria. It is the most common intracellular metabolism disorder of cobalamin. The early clinical form is the most frequent disorder and appears as a multisystemic disease with developmental delay, failure to thrive, and ocular, renal and hematological involvement during the first year of life. The thromboembolic events are associated with small vessel involvement, generating thrombotic microangiopathy responsible for renal involvement and pulmonary thromboembolism. The late-onset form is characterized by leukoencephalopathy, psychiatric disorders, subacute degeneration of the spinal cord, and thromboembolic events of medium to large vessels. The treatment currently available increases the survival of the patient and improves growth, neurological manifestations, biochemical, hematological profile and hydrocephalus. We present the neonatal debut of a case of CblC deficiency that appeared as a multisystem disease with initial neurological, ocular and hematological manifestations. The onset of symptoms was acute, a characteristic that is not frequent in CblC. The patient started treatment early, but in an unsatisfactory fashion, which led to increased neurological deterioration. Due to MRI images performed during the evolution of his condition, a superior and transverse sagittal sinus thrombosis, a rare manifestation of the disease, was observed.

La deficiencia de cobalamina C (CblC) es un defecto autosómico recesivo causado por la mutación del gen MMACHC, que resulta en la síntesis alterada de los cofactores metilcobalamina y adenosilcobalamina. Esto trae aparejado una disfunción de dos enzimas claves, lo cual genera hiperhomocisteinemia, hipometionimemia y aciduria metilmalónica. La presentación clínica de la deficiencia de CblC es heterogénea, y varía desde las formas de inicio temprano graves y potencialmente mortales, hasta los fenotipos más leves de inicio tardío. La forma clínica temprana es la más frecuente y se manifiesta como una enfermedad multisistémica, con restricción del desarrollo, restricción del crecimiento y alteraciones oculares, renales y hematológicas durante el primer año de vida. Las manifestaciones tromboembólicas están asociadas con el compromiso de pequeños vasos, lo que causa microangiopatía trombótica, responsable de compromiso renal y de tromboembolismo pulmonar. La forma tardía se caracteriza por leucoencefalopatía, trastornos psiquiátricos, degeneración subaguda de la médula espinal y eventos tromboembólicos de medianos o grandes vasos. El tratamiento disponible actualmente aumenta la supervivencia de la enfermedad y mejora el crecimiento, las manifestaciones neurológicas, el perfil bioquímico y hematológico y la hidrocefalia. Presentamos el debut neonatal de un caso de deficiencia de CblC que se manifestó con compromiso inicial neurológico, ocular y hematológico. El comienzo de los síntomas fue agudo, característica que no es frecuente en la deficiencia de CblC. El tratamiento se inició tempranamente, pero en forma insatisfactoria, con evolución de deterioro neurológico. En la evolución de su enfermedad en las imágenes de resonancia magnética, se puso de manifiesto trombosis de los senos sagital superior y transversos, una rara manifestación de la deficiencia de CblC.