To determine the effect of the genetic variations in CST3 gene on cerebral white matter changes, 7 polymorphisms (−82G/C, −78T/G, −5G/A, +4A/C, +87C/T, +148G/A and +213G/A) in CST3 gene have been analyzed, and checked their relation with laboratory data, cognitive impairment and MRI findings in healthy Japanese subjects. The gene discussed is CST3; the disease is Cognitive impairment.