Genetic Polymorphisms of the Mitochondrial Aldehyde Dehydrogenase ALDH2 Gene in a Large Ethnic Hakka Population in Southern China.

BACKGROUND Human mitochondrial aldehyde dehydrogenase 2 (ALDH2) plays a critical role in the detoxification of the ethanol metabolite acetaldehyde. The ALDH22 (rs671) gene variant is mainly absent among Europeans but is prevalent in populations in East Asia. The aim of this study was to investigate ALDH22 mutant alleles and genotype frequencies in the Hakka population of China. MATERIAL AND METHODS Between January 2016 and June 2017, 7,966 unrelated individuals were recruited into the study from the Hakka ethnic population residing in the Meizhou area of Guangdong Province, China, who provided venous blood samples. Genotyping of ALDH2 genotypes were determined using a gene chip platform and confirmed by DNA sequencing. RESULTS In the 7,966 individuals from the Hakka population of China in this study, the frequencies of the ALDH2 genotypes *1/*1, *1/2 and 2/2 were 52.03%, 39.67%, and 8.30%, respectively; 47.97% of the individuals were found to carry the ALDH22 genotype, which was associated with a deficiency in the aldehyde dehydrogenase (ALDH2) enzyme activity. The frequency of the ALDH22 allele was lower than that previously reported in the Japanese population but higher than that reported in other Oriental populations. CONCLUSIONS The findings of this study have provided new information on the ALDH2 gene polymorphisms in the Hakka ethnic population residing in the Meizhou area of Guangdong Province, China, including an understanding of the origin of the atypical ALDH22 allele. Also, the study findings may be relevant to the primary care of patients in China.