RESUMO
Background Two new SNPs have been recently associated to Alzheimer's disease in African American populations: FCGRIIB rs1050501 C/T, and PILRA rs1859788 A/G. The risk of Alzheimer's disease in FCGRIIB C and PILRA A allele carriers is three times higher than in non-carriers. However, the association between these and other single nucleotide polymorphisms (SNPs) has not been assessed. Methods Linkage disequilibrium analysis, with r= 0.8 as a threshold value, was used to impute new candidate SNPs, on genomic data from both genes in 26 populations worldwide (n= 2504) from the 1000Genomes database. Results Four SNPs (rs13376485, rs3767640, rs3767639 and rs3767641) were linked to rs1050501 and one (rs2405442) to rs1859788 in the whole sample. Conclusions Five novel SNPs could be associated with Alzheimer's disease susceptibility and play a causal role, even if none of them are exon variants since their potential roles in the regulation of gene expression.
Antecedentes Recientemente se han asociado dos nuevos polimorfismos de un solo nucleótido (SNP) a la enfermedad de Alzheimer en poblaciones afroamericanas: FCGRIIB rs1050501 C/T, y PILRA rs1859788 A/G. El riesgo de enfermedad de Alzheimer en los portadores de los alelos FCGRIIB C y PILRA A es tres veces mayor que en los no portadores. Sin embargo, no se ha evaluado la asociación entre estos y otros SNP. Métodos Se utilizó el análisis de desequilibrio de ligamiento, con r2= 0,8 como valor umbral, para imputar nuevos SNPs candidatos, sobre datos genómicos de ambos genes en 26 poblaciones de todo el mundo (n= 2504) de la base de datos 1000Genomes. Resultados Cuatro SNPs (rs13376485, rs3767640, rs3767639 y rs3767641) se vincularon al rs1050501 y uno (rs2405442) al rs1859788 en toda la muestra. Conclusiones Cinco nuevos SNP podrían estar asociados con la susceptibilidad a la enfermedad de Alzheimer y desempeñar un papel causal, aunque ninguno de ellos sea una variante de exón, dado su papel potencial en la regulación de la expresión génica.
RESUMO
The single-nucleotide polymorphisms (SNP) ILDR1 rs2332035 has shown a high statistical association with presbycusis (hearing loss with age or age-related hearing impairment (ARHI)), according to genetic association studies in European populations. However, linked markers have not been surveyed. Here linkage disequilibrium (LD) of markers in ILDR1, in relation to rs2332035, is explored in the 2504 individuals from the 1000Genomes database. Of the 920 SNPs retrieved, 10 showed strong LD (r2= 0.8) in Europeans and Latin Americans, which are proposed here as candidate markers for both control-case association and cause-effect studies in both populations.
