No evidence of the human chorionic gonadotropin-beta gene 5 βV79M polymorphism in Mexican women

Human chorionic gonadotropin (hCG) is a placental hormone essential for the maintenance of pregnancy. Previous studies have shown a G to A transition in exon 3 of the hCG beta gene 5, which changes the naturally occurring valine to methionine in codon 79. The frequency of this transition varies among different ethnic groups, being high in USA women, and less common, or absent, in various European populations. The purpose of the present study was to determine the frequency of the beta V79M allelic variant of the beta-subunit of hCG in a Mexican population, and to compare this frequency with those found in other ethnic groups. Placental DNA from 161 pregnant Mexican women was genotyped for the beta V79M by polymerase chain reaction (PCR)-restriction fragments length polymorphism analysis. No polymorphic beta V79M alleles were identified in the population studied. The allele and genotypic frequencies of beta V79M polymorphism in Mexican Mestizo women were significantly different from those reported for the US population, but not from five different European populations. In contrast to what has been found in women from the USA, it seems that the hCG beta V79M polymorphism is absent or extremely rare in Mexican Mestizo women.