Abstract

RENGIFO, Lucero; GAVIRIA, Duverney  and  SERRANO, Herman. APOE gene polymorphisms associated with Down syndrome in Colombian populations. Biomédica [online]. 2012, vol.32, n.2, pp.224-232. ISSN 0120-4157.

Introduction.Gene APOEε4 allele polymorphisms have been examined in Down syndrome because of the relationship between (a) the E4 isoform and (b) the type of Alzheimer´s dementia that appears in individuals with Down syndrome. This isoform is considered a risk factor for Alzheimer´s disease development and has been associated with early death in Down syndrome. Objectives. The polymorphisms in the APOE gene were characterized for Down syndrome individuals and their parents, in order to detect associations between the APOE polymorphisms and Down syndrome. Materials and methods. APOE gene polymorphisms were detected by RFLP-PCR and analyzed in 134 young individuals with Down syndrome, 87 mothers and 54 fathers, residents of the departments of Quindío and Risaralda, Colombia. The controls were 525 healthy individuals. Results. The APOEε3 allele and ε3/ε3 genotype were most frequent in all the populations (83-90% and 70-78%). The allelic frequency of APOEε2 was very low and ε2/ε2 (3-7%) was absent in Down syndrome and their parents. The allele APOEε4 was more frequent (11% vs. 9%) in Down syndrome individuals than in the controls. Comparing the allelic and genotypic frequencies between the populations with Down syndrome and their parents with the controls using Pearson c2 test and Fisher´s exact test odds ratio, no statistically significant differences were found. Conclusions. No statistically significant association was found between the polymorphisms of the APOE gene and Down syndrome. Sample size or ethnic influences may have affected these results. More studies are necessary with other Colombian populations to determine possible associations in other genes related to Alzheimer´s disease.

Keywords : apolipoprotein E; Down syndrome; Alzheimer´s disease; alleles; genotype; Colombia.

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