Lack of association between COMT Val158Met polymorphism and late-onset Alzheimer's disease in Han Chinese.

COMT (catechol-O-methyltransferase) has been conjectured to be associated with Alzheimer's disease (AD) due to its key role in cognitive function impairment by influencing the dopamine degradation in prefrontal cortex. A functional single nucleotide polymorphism (rs4680 SNP; G to A) in the COMT coding region causes Val158Met amino acid substitution in the corresponding protein, with Val allele exhibiting markedly 3- to 4-fold higher than Met in enzyme activity. Recent study reported that the functional rs4680 polymorphism within COMT gene was associated with susceptibility to AD in Caucasians. In order to examine the association between polymorphism in COMT gene and late-onset AD (LOAD) in a Han Chinese group, we analyzed the genotype and allele distributions of the COMT rs4680 polymorphism in a Han Chinese population consisting of 2291 individuals (1132 LOAD patients and 1159 healthy controls). In the present study, we find no significant association between the COMT rs4680 polymorphism and LOAD, even after statistical adjustment for age, gender and apolipoprotein E (APOE) status in the total sample as well as stratification for APOE status. Our results indicated that the COMT Val158Met polymorphism may not play a major role in the development of LOAD in Han Chinese.