Functional CLOCK gene rs1554483 G/C polymorphism is associated with susceptibility to Alzheimer's disease in the Chinese population

Objective: To examine the association between the circadian locomotor output cycles kaput (CLOCK) gene rs1554483 G/C polymorphism and susceptibility to Alzheimer's disease in Chinese people. Methods: This case-control study determined apolipoprotein E (APOE) and CLOCK rs1554483 G/C genotypes using polymerase chain reaction restriction fragment length polymorphism. Results: Unrelated patients with Alzheimer's disease (n = 130) and healthy controls (n = 188) were analysed for an association between the CLOCK gene rs1554483 G/C polymorphism and susceptibility to Alzheimer's disease. In the whole sample and in APOE epsilon 4 isoform noncarriers, the prevalence of CLOCK gene rs1554483 G allele carriers was significantly higher in patients with Alzheimer's disease than in controls. Among APOE epsilon 4 carriers, the prevalence of CLOCK rs1554483 G allele carriers was not significantly different between patients with Alzheimer's disease and controls. Conclusion: Among APOE epsilon 4 noncarriers, but not APOE epsilon 4 carriers, the CLOCK rs1554483 G allele was associated with increased susceptibility to Alzheimer's disease.