Association Between Aldehyde Dehydrogenase 2 Glu504Lys Polymorphism and Alcoholic Liver Disease

Background: Only a subset of patients with excessive alcohol use develop alcoholic liver disease (ALD), though the exact mechanism is not completely understood. Once ingested, alcohol is metabolized by 2 key oxidative enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). There are 2 major ALDH isoforms, cytosolic and mitochondrial, encoded by the aldehyde ALDH1 and ALDH2 genes, respectively. The ALDH2 gene was hypothesized to alter genetic susceptibility to alcohol dependence and alcohol-induced liver diseases. The aim of this study is to determine the association between aldehyde dehydrogenase 2 (rs671) glu504lys polymorphism and ALD. Methods: ALDH2 genotyping was performed in 535 healthy controls and 281 patients with ALD. Results: The prevalence of the common form of the single nucleotide polymorphism rs671, 504glu (glu/glu) was significantly higher in patients with ALD (95.4%) compared to that of controls (73.7%, P < 0.0001). Among controls, 23.7% had the heterozygous (glu/lys) genotype compared to 4.6% in those with ALD (odds ratio [OR] = 0.16, 95% CI: 0.09-0.28). The allele frequency for 504lys allele in patients with ALD was 2.3%, compared to 14.5% in healthy controls (OR = 0.13, 95% CI: 0.07-0.24). Conclusion: Patients with ALDH2 504lys variant were less associated with ALD compared to those with ALDH2 504glu using both genotypic and allelic analyses.