Cystic Fibrosis is a worldwide distributed hereditary disease. The incidence of the main (p.F508del) and other frequent mutations has been determined in a great number of countries and ethnic groups, but its incidence in most Latin American countries has remained unknown until recently. It is now beginning to be recognized as a frequent cause of infant mortality, and some countries report the incidence of their mutations. Colombia started several years ago a concerted program of molecular study of patients which were clinically diagnosed as probable cystic fibrosis. We screened the whole CFTR (ABCC7) coding sequence in 92 patients from 6 different geographic regions, using conventional PAGE analyses and DGGE followed by sequencing. Additionally, we established the frequency of the p.F508del mutation in 130 unrelated healthy controls. The results of this pilot study in Colombian patients from various ethnic admixture show six main mutations: p.F508del (41.8%), c.1811+1.6kbA>G (6.5%), p.G542X (3.8%), p.S549R (2.2%), p.W1282X (1.1%) and p.R1162X (1.1%). Thirteen other rare mutations, including three novel, were detected, accounting for a total of 63.6% known mutations. There is a great variability between the geographic regions, both in the frequency of the p.F508del mutation and non-p.F508del CF chromosomes. Our results point to a varied origin of the disease genes. These results also show that careful scrutiny of the mutations is needed in each part of Latin America in order to establish priority-screening protocols adapted to each country and region.

Adenylosuccinate lyase deficiency is an autosomal recessive defect of purine metabolism. Succinyladenosine (S-Ado) and succinylaminoimidazole carboxamide riboside (SAICAr) are the disease marker metabolites in physiological fluids. The Bratton-Marshall test for detection of SAICAr in urine has been added to the selective screening for inborn errors of metabolism that is carried out in our lab. During the last three years, around 2,000 patients have been screened by this method, resulting in the detection of four new cases with this disease. They all presented with severe psychomotor delay, hypotonia and refractory epilepsy since the neonatal period. The S-Ado/SAICAr ratio in cerebrospinal fluid was below 2, indicating that they correspond to the most severe form of the disease. New missense mutations were found in a heterozygous fashion in three patients. The study of purines in all patients with neurological disease of unknown etiology is highly recommended.

Introducción. La variabilidad genética del polimorfismo del gen APOE se considera un importante factor asociado a la predisposición a las enfermedades que afectan el metabolismo lipídico, a las enfermedades coronarias y a la enfermedad de Alzheimer, entre otras. En este sentido, es útil conocer este factor de riesgo en diferentes poblaciones y grupos étnicos. Objetivos. Analizar el polimorfismo del gen APOE y determinar las frecuencias alélicas y genotípicas de una muestra representativa de la población de Barranquilla, Colombia. Materiales y métodos. Se hizo en Barranquilla un estudio descriptivo y comparativo de 227 individuos no relacionados. Resultados. El alelo ε3 se presentó con mayor frecuencia (85 %), seguido del alelo ε4 (13 %) y, con menor frecuencia, el alelo ε2 (1,8 %). Los genotipos observados fueron los siguientes: ε3/ε3 en 71,8 %, ε3/ε4 en 24,2 %, ε2/ε3 en 2,2 %, ε2/ε4 en 1,3 % y ε4/ε4 en 0,4 %. El genotipo ε2/ε2 no se encontró en este estudio. La muestra representativa de la población estaba en equilibrio de Hardy-Weinberg. Conclusiones. Las frecuencias alélicas ε3 y el genotipo ε3/ε3 encontrados en la población estudiada, fueron similares a lo informado por la literatura científica en países como Brasil, México y Colombia, y en algunos grupos étnicos amerindios colombianos. No se encontró el genotipo ε2/ε2, resultado que coincide con otras poblaciones estudiadas a nivel mundial. La frecuencia del alelo ε4 y sus genotipos asociados en esta población, podría estar relacionada con la presencia de enfermedades como la hipercolesterolemia, el infarto de miocardio y la enfermedad de Alzheimer.Palabras clave: apolipoproteínas E, polimorfismo genético, población, alelos, Colombia. doi: http://dx.doi.org/10.7705/biomedica.v36i1.2612 APOE gene polymorphism analysis in Barranquilla, ColombiaIntroduction: The genetic variability present in the APOE gene polymorphism is considered an important factor associated with predisposition to diseases affecting lipid metabolism, as well as heart diseases and Alzheimer's disease, among others. Understanding it as a risk factor in different populations and ethnic groups is a useful tool. Objective: To analyze the APOE gene polymorphism and determine allelic and genotypic frequencies of a representative sample of population from Barranquilla, Colombia. Materials and methods:We performed a descriptive and comparative study. The sample size was 227 unrelated individuals from Barranquilla, Colombia Results: The most frequent allele was the ε3, with 85%, followed by the ε4 allele (13%) and ε2 (1.8%). The genotypes found were: ε3/ε3: 71.8%, ε3/ε4: 24.2%, ε2/ε3: 2.2%, ε2/ε4: 1.3% and ε4/ε4: 0.4%. The ε2/ε2 genotype was not found in this study. The sample exhibited the Hardy-Weinberg equilibrium. Conclusion: The frequency of the ε3 allele and the ε3/ε3 genotype was similar to that reported in the literature in countries like Brazil, Mexico, Colombia, and in some Colombian Amerindian ethnic groups. The ε2/ε2 genotype was absent. This result is consistent with those found in oth...

Objective: To study the NAT2 gene polymorphisms 481T, 590A and 857A in the Chimila, Wiwa and Wayuu indigenous groups of the Colombian Caribbean to determine the frequencies of the allelesNAT2*4, NAT2*5, NAT2*6, and NAT2*7 and to determine the types of acetylators present in these populations. Methods: A total of 202 subjects were studied: 47 Chimila, 55 Wiwa, and 100 Wayuu. The polymorphisms were idenjpgied using a real-time PCR method for allelic discrimination designed using Taqman of Applied Biosystems. Results: The following alleles were found at the highest frequency in the following groups: the NAT2*4 allele (wild type) in the Wayuu group (55.3%), the NAT2*5 allele in the Wiwa group (34.5%), and the NAT2*7 allele in the Chimila group (24.2%). A higher frequency of the rapid acetylator status was found in the Wayuu group (31.3%) and Chimila group (29.5%) compared with the Wiwa group (12.7%). The intermediate acetylator status distribution was very similar in all three groups, and the frequency of the slow acetylator status was higher in the Wiwa group (32.7%) compared with the Chimila and Wayuu groups (20.5% and 21.2%, respectively). Conclusion: The results demonstrated the allelic distribution and pharmacogenetic differences of the three groups studied and revealed the most frequent acetylator status and phenotype. Because of the high prevalence of slow acetylators, a greater incidence of tuberculosis (TB) drug-induced hepatotoxicity is predicted in these populations, with a higher frequency in the Wiwa group.

Introducción. La obesidad se considera un grave problema de salud pública y por ello se hacen esfuerzos en la búsqueda de genes como el LEP, el LEPR y el MC4R del sistema leptina-melanocortina, el cual opera en la regulación neuroendocrina de la ingestión y el equilibrio energético e influye en la patogenia de la enfermedad. Los resultados contradictorios en torno a la asociación de estos genes con la obesidad plantean la necesidad de nuevas investigaciones.Objetivo. Analizar los polimorfismos rs2167270 del gen LEP, rs1137101 del gen LEPR y rs17782313 del gen MC4R asociados con la obesidad y sus variables clínicas y bioquímicas en una muestra de pacientes adultos de Barranquilla.Materiales y métodos. Se estudiaron 111 personas obesas y 155 no obesas como controles. Los polimorfismos se determinaron mediante reacción en cadena de la polimerasa (PCR) en tiempo real. Se tomaron las medidas antropométricas, se evaluó la presión arterial y se hicieron pruebas bioquímicas.Resultados. No se encontraron diferencias estadísticas en la frecuencia alélica y genotípica de los polimorfismos en los grupos estudiados. En cuanto a las variables clínicas y bioquímicas, el genotipo CC del polimorfismo rs17782313 del gen MC4R, se asoció con un aumento de la presión arterial sistólica y, el alelo T y su genotipo homocigoto, con una disminución del colesterol HDL en los obesos. No se evidenció ningún efecto de los otros polimorfismos en estas variables.Conclusiones. Los polimorfismos rs2167270 del gen LEP, rs1137101 del gen LEPR y rs17782313 del gen MC4R, no se asociaron con obesidad en la población analizada. Se encontró que el polimorfismo rs17782313 del gen MC4R influyó en el aumento de la presión arterial sistólica y la disminución del colesterol HDL en las personas obesas.

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