Distribution of three SNPs related to low bone mineral density in Amerindian groups and Mestizos from Mexico

Abstract

Objectives: Some Single nucleotide polymorphisms (SNPs) of several candidate genes have been associated with low bone mineral density (BMD) and fracture risk. As the genetic variability of such SNPs in Hispanic and Native American populations is scarce, we analyzed the three SNPs that have been related with bone mass disorders (Sp1, A163G, and BsmI) located in the genes of Type I Collagen (COL1A1), Osteoprotegerin (OPG), and Vitamin D receptor (VDR) in Mexican Mestizos (people resulting from post-Columbian admixture) and five Amerindian populations.

Methods: We genotyped these three SNPs by Polymerase chain reaction (PCR) and Restriction fragment length polymorphisms (RFLPs) in 523 individuals from five Mexican Amerindian groups (Nahua, Maya, Purépecha, Tarahumara, and Huichol) and 227 western Mestizos (Jalisco state).

Results: The modal allele was the same in all the six populations for Sp1-COL1A1 (S > 77%), A163G-OPG (A > 80%), and BsmI-VDR (b > 62%). Genotype distribution was in Hardy-Weinberg equilibrium in all SNPs/populations, excepting Sp1-COL1A1 in the Purépecha group and BsmI-VDR in Mestizo. In terms of the presumably Sp1-COL1A1 risk allele to low BMD (allele "s"), the Purépecha group showed the highest allele (23%) and homozygous (14.5%) frequencies. If the role of this allele as a genetic predisposing factor to low BMD were confirmed, this would mean increased susceptibility of Purépechas with regard to Europeans (14.5 vs. 6.8%).

Conclusions: This finding presumably could influence the genetic susceptibility to low BMD in Purépechas. For the SNPs, BsmI-VDR and A163G-OPG, relative homogeneity was observed among the Mexican populations analyzed here.