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INTRODUCTION: Type III glycogen storage disease (GSD III) is an autosomal recessive disorder in which a mutation in the AGL gene causes deficiency of the glycogen debranching enzyme. The disease is characterized by fasting hypoglycemia, hepatomegaly and progressive myopathy. Molecular analyses of AGL have indicated heterogeneity depending on ethnic groups. The full spectrum of AGL mutations in Colombia remains unclear. OBJECTIVE: To describe the clinical and molecular characteristics of ten Colombian patients diagnosed with GSD III. MATERIALS AND METHODS: We recruited ten Colombian children with a clinical and biochemical diagnosis of GSD III to undergo genetic testing. The full coding exons and the relevant exon-intron boundaries of the AGL underwent Sanger sequencing to identify mutation. RESULTS: All patients had the classic phenotype of the GSD III. Genetic analysis revealed a mutation p.Arg910X in two patients. One patient had the mutation p.Glu1072AspfsX36, and one case showed a compound heterozygosity with p.Arg910X and p.Glu1072AspfsX36 mutations. We also detected the deletion of AGL gene 3, 4, 5, and 6 exons in three patients. The in silico studies predicted that these defects are pathogenic. No mutations were detected in the amplified regions in three patients. CONCLUSION: We found mutations and deletions that explain the clinical phenotype of GSD III patients. This is the first report with a description of the clinical phenotype and the spectrum of AGL mutations in Colombian patients. This is important to provide appropriate prognosis and genetic counseling to the patient and their relatives.

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Resumen Introducción. La enfermedad por almacenamiento de glucógeno de tipo III es una alteración autosómica recesiva, en la cual las mutaciones del gen AGL causan una deficiencia en la enzima desramificadora de glucógeno. Se caracteriza por hipoglucemia, hepatomegalia y miopatías progresivas. El análisis molecular del gen AGL ha evidenciado mutaciones que difieren según la población estudiada. En la actualidad, no existen reportes que describan mutaciones en el AGL de pacientes colombianos con esta condición. Objetivo. Describir las características clínicas y moleculares de diez pacientes colombianos con enfermedad por almacenamiento del glucógeno de tipo III. Materiales y métodos. Se analizaron diez pacientes pediátricos colombianos con la enfermedad y se hizo su estudio genético mediante la secuenciación de las regiones que codifican y las intrónicas circundantes del gen AGL con el método de Sanger. Resultados. Todos los pacientes tenían el fenotipo clásico de la enfermedad. El estudio genético reveló la mutación p.Arg910X en dos pacientes. Uno presentó la mutación p.Glu1072AspfsX36 y otro resultó heterocigoto compuesto con las mutaciones p.Arg910X y p.Glu1072AspfsX36. Asimismo, en tres pacientes se detectó la deleción de los exones 4, 5 y 6 del gen AGL. Los estudios de simulación computacional predijeron que estos defectos eran patogénicos. En tres pacientes no se encontraron mutaciones en las regiones amplificadas. Conclusión. Se encontraron mutaciones y deleciones que explican el fenotipo clínico de los pacientes. Este es el primer reporte en el que se describe el fenotipo clínico y el espectro de mutaciones en el gen AGL de pacientes colombianos, lo cual es importante para ofrecer un apropiado pronóstico, y asesoría genética al paciente y a su familia.

Abstract Introduction: Type III glycogen storage disease (GSD III) is an autosomal recessive disorder in which a mutation in the AGL gene causes deficiency of the glycogen debranching enzyme. The disease is characterized by fasting hypoglycemia, hepatomegaly and progressive myopathy. Molecular analyses of AGL have indicated heterogeneity depending on ethnic groups. The full spectrum of AGL mutations in Colombia remains unclear. Objective: To describe the clinical and molecular characteristics of ten Colombian patients diagnosed with GSD III. Materials and methods: We recruited ten Colombian children with a clinical and biochemical diagnosis of GSD III to undergo genetic testing. The full coding exons and the relevant exon-intron boundaries of the AGL underwent Sanger sequencing to identify mutation. Results: All patients had the classic phenotype of the GSD III. Genetic analysis revealed a mutation p.Arg910X in two patients. One patient had the mutation p.Glu1072AspfsX36, and one case showed a compound heterozygosity with p.Arg910X and p.Glu1072AspfsX36 mutations. We also detected the deletion of AGL gene 3, 4, 5, and 6 exons in three patients. The in silico studies predicted that these defects are pathogenic. No mutations were detected in the amplified regions in three patients. Conclusion: We found mutations and deletions that explain the clinical phenotype of GSDIII patients. This is the first report with a description of the clinical phenotype and the spectrum of AGLmutations in Colombian patients. This is importantto provide appropriate prognosis and genetic counseling to the patient and their relatives.

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Introduction: One of the most important risk factors for hepatocellular carcinoma (HCC) is alcohol consumption: Studies in different populations suggest that the risk of liver disease could be associated with genetic variants of the enzymes involved in alcohol metabolism, such as alcohol dehydrogenase (ADH) and cytochrome P450 CYP2E1. Objective: To identify and characterize the allelic variants of ADH1B, ADH1C and CYP2E1 genes in Colombian patients with cirrhosis and/or HCC. Materials and methods: We included samples from patients attending the hepatology unit between 2005-2007 and 2014-2016 of a hospital in Medellin. Samples were genotyped using PCR-RFLP. We compared the results with two control groups and the 1000 Genomes Project database. Results: We collected 97 samples from patients with a diagnosis of cirrhosis and/or HCC. The two main risk factors were chronic alcohol consumption (18.6%) and cholangiopathies (17.5%). The most frequent genotypes in the study population were ADH1B*1/1 (82%), ADH1C*1/1 (59%), and CYP2E1*C/C (84%). Conclusions: This first study of polymorphisms in Colombian patients diagnosed with cirrhosis and/or HCC showed genotypes ADH1B*1/1, ADH1C*1/1 and CYP2E1*C/C as the most frequent. We found no significant differences in the genotype frequency between cases and controls. Further studies are necessary to explore the association between polymorphisms and the risk of end-stage liver disease from alcohol consumption.

Introducción. Uno de los principales factores de riesgo del carcinoma hepatocelular es el consumo crónico de alcohol. En estudios en diferentes poblaciones, se sugiere que las variantes genéticas de las enzimas que participan en el metabolismo del alcohol, como la alcohol deshidrogenasa (ADH) y la citocromo P450 (CYP2E1), estarían asociadas con riesgo de enfermedades hepáticas terminales.Objetivo. Identificar y caracterizar las variantes alélicas de los genes ADH1B, ADH1C y CYP2E1 en pacientes colombianos con diagnóstico de cirrosis y carcinoma hepatocelular.Materiales y métodos. Se incluyeron muestras de pacientes atendidos entre el 2005 y el 2007, y entre el 2014 y el 2016, en la unidad de hepatología de un hospital de Medellín. La genotipificación de las muestras se hizo mediante reacción en cadena de la polimerasa (Polymerase Chain Reaction, PCR) con análisis de los polimorfismos en la longitud de los fragmentos de restricción (Restriction Fragment Length Polymorphism, RFLP). Los resultados se compararon con los de dos grupos de control y con lo reportado en la base de datos del 1000 Genomes Project.Resultados. Se recolectaron 97 muestras de pacientes con diagnóstico de cirrosis y carcinoma hepatocelular. Los dos factores de riesgo más frecuentes fueron el consumo crónico de alcohol (18,6 %) y las colangiopatías (17,5 %). Los genotipos más frecuentes en la población de estudio fueron el ADH1B*1/1 (82 %), el ADH1C*1/1 (59 %) y el CYP2E1*C/C (84 %).Conclusiones. En este primer estudio de los polimorfismos en pacientes colombianos con diagnóstico de cirrosis y carcinoma hepatocelular, los genotipos más frecuentes fueron el ADH1B*1/1, el ADH1C*1/1 y el CYP2E1*C/C. No se observaron diferencias estadísticamente significativas en la frecuencia de los genotipos entre los casos y los controles. Se requieren estudios adicionales en población colombiana para evaluar el riesgo de la enfermedad hepática terminal por consumo crónico de alcohol y laasociación con los polimorfismos.

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BACKGROUND: Hepatitis B Virus (HBV) infection is a worldwide public health problem. In the 1980's a highly effective and safe vaccine against HBV was developed, although breakthrough infection still occasionally occurs because of the emergence of escape mutants. The aim of this study was to identify HBV genotypes and escape mutants in children and their mothers in Amerindian communities of the Amazonas State, Southern Colombia. METHODS: Blood specimens collected from children and mothers belonging to 37 Amerindian communities in Amazonas state, were screened for HBsAg and anti-HBc using ELISA. The partial region containing the S ORF was amplified by nested PCR, and amplicons were sequenced. The phylogenetic analysis was performed using the MEGA 5.05 software. RESULTS: Forty-six children (46/1275, 3.6%) and one hundred and seventy-seven mothers (177/572, 30.9%) were tested positive for the anti-HBc serological marker. Among them, 190 samples were tested for viral genome detection; 8.3% (2/31) serum samples obtained from children and 3.1% (5/159) from mothers were positive for the ORF S PCR. The predominant HBV genotype in the study population was F, subgenotype F1b; in addition, subgenotype F1a and genotype A were also characterized. Two HBV escape mutants were identified, G145R, reported worldwide, and W156*; this stop codon was identified in a child with occult HBV infection. Other mutations were found, L109R and G130E, located in critical positions of the HBsAg sequence. CONCLUSIONS: This study aimed to characterize the HBV genotype F, subgenotypes F1b and F1a, and genotype A in Amerindian communities and for the first time escape mutants in Colombia. Further investigations are necessary to elucidate the frequency and the epidemiological impact of the escape mutants in the country.

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BACKGROUND: Hepatitis E virus is a major cause of outbreaks as well as sporadic hepatitis cases worldwide. The epidemiology of this enterically transmitted infection differs between developing and developed countries. The aims of this study were to describe HEV infection in Colombian patients and to characterize the genotype. METHODS: A prospective study was carried out on 40 patients aged over 15 with a clinical diagnosis of viral hepatitis, recruited from five primary health units in the city of Medellin, Colombia. Fecal samples obtained from the 40 consecutives cases were analyzed for HEV RNA using nested reverse transcription PCR for both ORF1 and ORF2-3. The amplicons were sequenced for phylogenetic analyses. RESULTS: Nine (22.5%) cases of HEV infection were identified in the study population. Three HEV strains obtained from patients were classified as genotype 3. No significant association was found between cases of Hepatitis E and the variables water drinking source, garbage collection system and contact with pigs. CONCLUSIONS: This is the first prospective study of hepatitis E in Colombian patients. The circulation of the genotype 3 in this population is predictable considering the reports of the region and the identification of this genotype from pigs in the state of Antioquia, of which Medellin is the capital. Further studies are necessary to establish whether zoonotic transmission of HEV is important in Colombia.

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BACKGROUND: Hepatitis C virus (HCV) infects 170 million persons worldwide and is a public health problem. Considering that HCV is principally transmitted by exposure to infected blood, multi-transfused patients constitute one of the most important risk groups in developing countries. To explore the dynamics of this infection in Colombia, we performed a study to determine the genotypes of HCV in a cohort of multi-transfused patients. RESULTS: The serum samples from patients positive for anti-HCV were evaluated for HCV RNA by nested-PCR of the 5'untranslated region (5'UTR). Viral genotype was determined by RFLP and/or automated sequencing. HCV subtype 1b was found in eight cases (66.7%) and subtype 1a in two cases (16.7%); seven isolates of subtype 1b were obtained from patients who had received the first transfusion before 1986. Either genotypes 2b (8.3%) or 3a (8.3%) were found in the remaining positive specimens. CONCLUSIONS: This is the first HCV genotyping study developed in multi-transfused patients in Colombia where HCV subtype 1b was the most prevalent. The mutation G235A in the 5'UTR of three isolates generated an additional restriction site and an RFLP pattern different from those previously described for genotype 1.

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