The deletion allele of the angiotensin I converting enzyme gene as a genetic susceptibility factor for cognitive impairment.

Experimental evidences suggest an implication of the renin angiotensin system (RAS) as a potential determinant of cognitive functions. To explore this hypothesis, we compared the distribution of an insertion (I)/deletion (D) polymorphism of the gene coding for the angiotensin I converting enzyme (ACE), a key enzyme of the RAS, in 228 elderly with cognitive impairment to that of 255 controls. The ACE D allele frequency was higher in the group with cognitive impairment (0.594) than in controls (0.514) (P < 0.02). The ACE DD genotype carriers had an increased risk of cognitive impairment (OR = 1.60, 95% CI (1.04-2.36), P < 0.03), independent of other risk factors of cognitive impairment: age, gender and presence of the apolipoprotein E epsilon 4 allele. This association was stronger in men (OR = 3.25, 95% CI (1.40-7.58), P < 0.006). This result suggests a possible implication of the RAS in human brain and cognitive functions.