Age-dependent association of KIBRA gene polymorphism with Alzheimer's disease in Han Chinese.

Genetic factors play an important role in the Alzheimer's disease (AD) development and memory impairment is a cardinal clinical feature of AD. Kidney and brain expressed protein (KIBRA), owing to its connection with human episodic memory, became an interesting candidate gene for AD. Recently, KIBRA (rs17070145) was reported to be associated with AD in the genetic and functional levels in Caucasian and African-American, and the association might be different across age groups. To investigate the possibility of age-dependent association of KIBRA with AD in Asian, we conducted an independent replication study in a cohort of 1,586 subjects from Han Chinese (including 790 LOAD patients and 796 healthy controls). The results revealed no significant differences in the distributions of genotype or allele between LOAD and control groups in the total sample. However, when these data were stratified by their age, we observed a significant difference in the genotypes and alleles frequencies (genotype: p = 0.004, allele: p = 0.035) in the young subgroup. Moreover, the association was further demonstrated in logistic regression analysis (rs17070145: p = 0.045, OR = 0.428). Our data suggested that KIBRA might associate with younger AD patients (≤74 years) in a Northern Han Chinese population.