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Angiotensin-I converting enzyme genotypes and left ventricular hypertrophy in patients with hypertrophic
M Lechin1, M A Quiñones, A Omran
1Department of Medicine, Baylor College of Medicine, Houston, Tex, USA.
Insights
Genetic variations in the angiotensin-I converting enzyme (ACE) gene influence the severity of left ventricular hypertrophy (LVH) in hypertrophic cardiomyopathy (HCM) patients. This study found ACE genotypes are linked to differences in LVH extent and left ventricular mass index (LVMI).
Area of Science:
- Cardiovascular Genetics
- Molecular Cardiology
- Genetic Epidemiology
Background:
- Phenotypic variability in hypertrophic cardiomyopathy (HCM) suggests genetic modifiers.
- Angiotensin-I converting enzyme (ACE) gene variants are linked to cardiac hypertrophy.
Purpose of the Study:
- To investigate if ACE gene polymorphisms affect the phenotypic expression of left ventricular hypertrophy (LVH) in HCM patients.
- To determine the association between ACE genotypes and left ventricular mass index (LVMI) and LVH extent.
Main Methods:
- 183 HCM patients underwent echocardiography for LVMI and LVH scoring.
- DNA analysis using polymerase chain reaction (PCR) for ACE genotyping (DD, ID, II).
- Statistical analysis including regression to assess genotype-phenotype correlations.
Main Results:
- ACE genotypes DD, ID, and II were found in 60, 90, and 33 HCM patients, respectively.
- Patients with the DD genotype showed significantly higher LVMI and LVH scores compared to ID/II genotypes (P=.046 and P=.004).
- ACE genotypes accounted for 3.7% and 6.5% of LVMI and LVH score variability, respectively.
Conclusions:
- ACE gene polymorphisms significantly influence the phenotypic expression of cardiac hypertrophy in HCM.
- The DD genotype is associated with a more pronounced hypertrophic phenotype in HCM patients.
Background:
The variability of the phenotypic expression of left ventricular hypertrophy (LVH) in patients with hypertrophic cardiomyopathy (HCM) indicates a potential role for additional modifying genes. Variants of angiotensin-I converting enzyme (ACE) gene have been implicated in cardiac hypertrophy. To assess whether ACE genotypes influence the phenotypic expression of hypertrophy, we determined the left ventricular mass index (LVMI) and extent of hypertrophy in 183 patients with HCM.
Methods And Results:
LVMI was derived by the area-length method using two-dimensional echocardiograms. Extent of LVH was determined by a point score method (1 to 10 points). DNA was extracted from blood, and ACE genotyping was performed by polymerase chain reaction (PCR) with an established protocol. Amplification of DNA in the region of polymorphism by PCR of alleles I and D showed 490- and 190-bp products, respectively. ACE genotypes DD, ID, and II were present in 60, 90, and 33 patients with HCM, respectively. In genetically independent patients (n = 108), the mean LVMI (g/m2) was 148 +/- 35.3 in those with DD (n = 35) and 134.2 +/- 33.3 in those with ID and II (n = 73) genotypes (P = .046). LVH score was 6.69 +/- 1.71 in patients with DD and 5.55 +/- 2.19 in those with ID and II genotypes (P = .004). Regression analysis showed that ACE genotypes accounted for 3.7% and 6.5% of the variability of LVMI and LVH score (P = .046 and P = .008, respectively). In 26 patients from a single family, LVMI and LVH score were also greater in patients with DD than in those with ID and II genotypes. ACE genotypes accounted for 14.7% and 10.4% of the variability of the LVMI and extent of hypertrophy, respectively.
Conclusions:
ACE genotypes influence the phenotypic expression of hypertrophy in HCM.