Association of ACE genotype and predominantly diastolic hypertension: a preliminary study

Abstract

Background: The insertion/deletion (I/D) angiotensin-converting enzyme (ACE) polymorphism has been established as a cardiovascular risk factor in some populations, but the association with essential hypertension is controversial. Predominantly diastolic hypertension (PDH), or narrow pulse pressure hypertension, has been shown to have increased peripheral resistance. Because a DD genotype has been associated with higher plasma ACE levels and angiotensin II activity, we genotyped PDH patients for ACE I/D polymorphism.

Methods: Ninety-three patients with systolic blood pressure (BP)<140 mmHg systolic and diastolic BP>90 mmHg, or BP>140/90 mmHg with a pulse pressure<45 mmHg, were defined as PDH. The II, ID and DD genotype variants of ACE were characterised by the triple primer nested-PCR method. Results were compared to 75 normotensive control individuals. Statistical significance was assessed by the Chi square test.

Results: The genotype distribution among PDH patients was II=20 (21.5%), ID=34 (36.5%), DD=39 (42%), while the distribution among normotensive controls was II=16 (21.4%), ID=42 (56%), DD=17 (22.6%). The difference in genotype distribution between PDH patients and controls was significant (p<0.02). ACE allele frequencies in PDH patients and controls were D=0.60, I=0.40 and D=0.51, I=0.49, respectively, statistically non-significant (ns).

Conclusion: These results suggest an association between ACE genotype DD and predominantly diastolic hypertension.