Lack of association between the insertion/deletion polymorphism of the angiotensin-converting enzyme gene and idiopathic dilated cardiomyopathy.

OBJECTIVES: We sought to investigate the role of polymorphisms of the gene for angiotensin-converting enzyme in the development and progression of idiopathic dilated cardiomyopathy.
BACKGROUND: Cardiovascular renin-angiotensin systems may be involved in cardiac remodeling and fibrosis. The absence (deletion [D]) of a 287-base pair marker in the angiotensin-converting enzyme gene (introm 16) is associated with increased serum angiotensin-converting enzyme levels. The DD genotype may be a risk factor for the development of end-stage heart failure due to cardiomyopathy. We therefore examined the relation of the angiotensin-converting enzyme genotype to idiopathic dilated cardiomyopathy and to markers of disease severity.
METHODS: We studied 364 control subjects and 99 consecutive patients with idiopathic dilated cardiomyopathy. When the incidence of the DD genotype in our control group was assumed to be similar to that previously reported (27%), this study had a power of 0.9 to detect a different incidence in the patient group, if the true incidence in patients was 42%. Deoxyribonucleic acid (DNA) was isolated from blood samples, and angiotensin-converting enzyme genotype was determined by specific polymerase chain reaction and separation of amplified fragments by agarose gel electrophoresis. We also compared genotype distribution with that in previously reported European control subjects. Functional status, clinical course over a mean +/- SD of 28 +/- 33 months and outcome were documented. Cardiac morphology and function and evidence of rhythm disturbance were noninvasively determined.
RESULTS: Angiotensin-converting enzyme genotype distribution and allele frequencies were similar in patients and control subjects to within 10% (with 95% confidence) and were also similar between patients and European control subjects. No markers of disease severity or progression other than duration of symptoms before diagnosis and the number of ventricular ectopic beats/h were significantly associated with the presence of the DD alleles.
CONCLUSIONS: We find no evidence to support an association between angiotensin-converting enzyme genotype and either the diagnosis of idiopathic dilated cardiomyopathy itself or progression of the disease.