Frequency of ALDH2 Gene Polymorphism (rs671) in Dayak, Javanese, Minahasan, and Papuan Ethnic Populations

Abstract

The rs671 single nucleotide polymorphism (SNP) in the ALDH2 gene results in ALDH2 enzyme inactivation, impairing acetaldehyde detoxification. Individuals carrying the ALDH2*2 allele are at increased risk for alcohol-related diseases. The rs671 polymorphism is common in East Asia, likely originating from the Han-Chinese ethnic group. Studies in Indonesia report high variability in the frequency of the ALDH2*2 allele, ranging from 15.5 % to 72.6 %, raising questions about why its prevalence in Indonesia exceeds that of China. This study aimed to determine the genotypic and allele frequencies of rs671 among Indonesians from different eth-nic backgrounds, including the Dayak, Javanese, Minahasan, and highland Papuan groups. SNP rs671 was detected using the TaqMan SNP genotyping assay on the QuantStudio 5 real-time PCR system. In the Minahasan group, the genotypic fre-quencies were 97.8 % typical homozygous (ALDH2*1/*1), 2.2 % heterozygous (ALDH2*1/*2), and 0 % atypical homozygous (ALDH2*2/*2), with an allele fre-quency of 1.1 % for ALDH2*2. In contrast, the Dayak, Javanese, and highland Pa-puan groups exhibited 100 % typical homozygotes (ALDH2*1/*1), with no rs671 variants detected. These results suggest a lower prevalence of rs671 SNPs in the Minahasan group and the absence of variants in Javanese and highland Papuan populations, differing from prior reports. The absence of rs671 in highland Papuans indicates that this polymorphism likely emerged and spread after the divergence of East Asian and Papuan populations. Further studies are needed to elucidate the evolutionary and migratory history of rs671 in Southeast Asia.