Polymorphism of CLOCK gene rs 4580704 C > G is associated with susceptibility of Alzheimer's disease in a Chinese population

Background and aims: The association of polymorphism of circadian locomotor output cycle kaput (CLOCK) gene rs 4580704 C/G with susceptibility of Alzheimer's disease (AD) was examined in the present study.

Methods: This was a case/control study and investigated the association of polymorphism of CLOCK gene rs 4580704 C/G with susceptibility of AD. Genotypes of apolipoprotein E (APOE) and CLOCK gene rs 4580704 C/G were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) detection method.

Results: This study was comprised of 296 unrelated AD patients and 423 controls. We performed an analysis the association of polymorphism of CLOCK gene rs 4580704 C/G with susceptibility of AD. In the whole sample or APOEε4 noncarriers, prevalence of C carriers in CLOCK gene rs 4580704 in AD patients was significantly higher than in controls (in the whole sample: χ(2) = 13.773, p <0.0001; in APOEε4 noncarriers: χ(2) = 51.588, p <0.0001). However, among APOEε4 carriers, prevalence of C carriers in CLOCK gene rs 4580704 between patients and controls was not statistically significant (χ(2) = 0.753, p = 0.386).

Conclusions: Among APOEε4 noncarriers, C carriers in CLOCK gene rs 4580704 were associated with a high susceptibility of AD; however, among APOEε4 carriers the functional polymorphism of clock gene rs 4580704 C/G was not associated with AD susceptibility.