3. Genetic factors
3.1. Genetic Susceptibility to Alcoholism
Increased levels of acetaldehyde, the toxic intermediary product of alcohol metabolism may result
from polymorphism of the loci encoding alcohol dehydrogenase (ADH) and or acetaldehyde
dehydrogenase (ALDH2) [6]. Several studies reported high polymorphism (*) among alcohol abusing
persons. Associations between high ADH3*2 and low ADH 2*2 and ALDH*2 alleles were found
frequently among alcohol dependent men in Mexico [7]. Both ALDH2*1/*2 and ALDH2*2/*2 were
lower and ADH2*1/*1 and ALDH2*1/*1 higher among alcoholic Korean men [8]. The ADH2*1
genotype was increased among alcoholics and the coexistence of ADH2*1/*1 and ALDH2*1/*1 was
6.4−9.6 enhanced among Japanese alcoholics compared to controls [9]. Mexican-Americans were
found to have high frequency of the allele CYP2E1c2 which is associated with early onset
alcoholism [10].