A functional variant of ALDH1A2 is associated with hand osteoarthritis in the Chinese population

Genome-wide association study identified common variants within the ALDH1A2 gene as the susceptible loci of hand osteoarthritis (HOA) in UK and Iceland populations. Located in chromosome 15, ALDH1A2 encodes aldehyde dehydrogenase family 1 member A2, which is an enzyme that catalyses the synthesis of retinoic acid from retinaldehyde. Our purposes were to replicate the association of functional variant in ALDH1A2 with the development of HOA in the Chinese population. Variant rs12915901 of ALDH1A2 was genotyped in 872 HOA patients and 1223 healthy controls. Subchondral bone samples were collected from 40 patients who had undergone a trapeziectomy, and the tissue expression of ALDH1A2 was analysed. The chi-square analysis was used to compare the frequency of genotype and risk allele between the HOA cases and controls. The Student t test was used to compare the mRNA expression of ALDH1A2 between patients with genotype AA/AG and those with genotype GG. The frequency of genotype AA was significantly higher in HOA patients than in the controls (7.6% vs. 5.1%, p = .01). The frequency of allele A was significantly higher in the patients than in the controls (28.9% vs. 24.6%, p = .005). The mRNA expression of ALDH1A2 was 1.31-folds higher in patients with genotype GG than in the patients with genotype AA/AG (0.000617 ± 0.000231 vs. 0.000471 ± 0.000198, p = .04). Variant rs12915901 of ALDH1A2 contributed to the susceptibility of HOA in the Chinese population. Allele A of rs12915901 can add to the risk of HOA possibly via down-regulation of ALDH1A2 expression.