On the basis of the above-mentioned initial findings about of the influence of these polymorphisms on cardiovascular profile, the aim of the present study was to define the interaction between Clock T3111C and Per2 C111G, ApoE ε4, and cognitive function, in relation to cardiovascular risk factors, in SCD and MCI patients and in the progression to AD. The gene discussed is APOE; the disease is Schnyder corneal dystrophy.