Glycogen synthase kinase-3β (GSK-3β) rs334558 polymorphism is not associated with mild cognitive impairment in Chinese Han type 2 diabetic patients

Background and objective: Activation of glycogen synthase kinase-3 beta (GSK-3 beta) increases the risk of insulin resistance and type 2 diabetes mellitus (T2DM). Considering the association between GSK-3 beta rs334558 polymorphism and Alzheimer's disease, we aimed to investigate the association between GSK-3 beta rs334558 polymorphism and mild cognitive impairment (MCI) in T2DM patients. Methods: This case-control study was performed to evaluate the association between GSK-3 beta rs334558 polymorphism and MCI in the recruited 88 Chinese Han T2DM patients, 51 of which satisfied the MCI diagnostic criteria and 37 matched individuals with healthy cognition as the control. Results: Genotype and allele distributions of GSK-3 beta rs334558 polymorphism in the MCI patients were not significantly different from those in healthy-cognition controls (Chi(2) = 4.377, df = 2, P = 0.112 and Chi(2) = 0.031, df = 1, P= 0.859, respectively). There was no significant difference in the serum GSK-3 beta concentration between the two groups (16.40 +/- 16.61 ng/ml vs. 18.63 +/- 16.07 ng/ml, P > 0.05). Nor difference was found between the two groups in terms of GSK-3 beta genotypes (CC, TC and TT, all P > 0.05). Neuropsychological test scores were not significantly different between genotypic subgroups in either the MCI group or control group (all P > 0.05). Conclusions: Our findings failed to identify the association between the GSK-3 beta rs334558 polymorphism and diabetic MCI. GSK-3 beta rs334558 polymorphism might not be a stratification marker to predicate the disease risk in China.