Dual Effect of PER2 C111G Polymorphism on Cognitive Functions across Progression from Subjective Cognitive Decline to Mild Cognitive Impairment

Periodic circadian protein homolog 2 (PER2) has a role in the intracellular signaling pathways of long-term potentiation and has implications for synaptic plasticity. We aimed to assess the association of PER2 C111G polymorphism with cognitive functions in 45 individuals with subjective cognitive decline (SCD). All participants were followed-up every 12 or 24 months for a mean time of 9.87 ± 4.38 years. During follow-up 34.88% of patients progressed to mild cognitive impairment (MCI). We found that PER2 C111G polymorphism was associated with better language performance in SCD patients, but was associated with faster cognitive decline as patients progress to MCI.