Population difference in the association of BDNF promoter methylation with mild cognitive impairment in the Xinjiang Uygur and Han populations

• No association of BDNF methylation with MCI was found in either Uygur or Han Chinese populations.
• BDNF methylation levels of male Xinjiang Han MCI cases were higher than male Xinjiang Uygur MCI cases.
• BDNF methylation levels were significantly higher in Xinjiang Han Chinese in than Ningbo Han Chinese.
• The differences of populations and environments may affect levels of BDNF methylation.

BackgroundMild cognitive impairment (MCI) is a clinical transitional stage between normal aging and Alzheimer disease, which leads to memory loss and a reduction in cognitive function. Brain derived neurotrophic factor (BDNF) plays an important role in neuronal development and plasticity. The aim of this study was to explore the association between BDNF promoter methylation and MCI in the Xinjiang Uygur and Han populations.MethodsA DNA methylation assay using bisulfite pyrosequencing technology was performed on 96 Uygur and 96 Han Chinese individuals from Xinjiang province, China.ResultsWe found a significantly higher BDNF methylation level in Han MCI cases than in Uygur MCI cases in males from Xinjiang province (p=0.022). In addition, the methylation level was significantly higher in Xinjiang Han healthy Chinese individuals (Northwestern China) than in Ningbo Han healthy Chinese individuals (Southeastern China) (Female and Male: p=1.17E−05; Female: p=0.020; Male: p=1.37E−04). But our results showed no significant association of BDNF methylation with MCI in either the Uygur or Han Chinese populations (p>0.05). Further gender-based subgroup analyses did not find any significant results (p>0.05).ConclusionOur results indicate that different levels of BDNF methylation may be present in different populations and environments. This study also provides further information regarding the relationship between BDNF methylation levels and MCI in Xinjiang Uygur and Han ethnic groups.