Background: Angiotensin converting enzyme (ACE) catayzes the formation of angiotensin I to angiotensin II. A polymorphism has been identified in intron 16 in which a 287 base-pair alu sequence was found to be present (insertion or I) or absent (deletion or D) in the population. ACE and the components of the renin-angiotensin system are expressed in adipose tissue and therefore the I/D polymorphism within ACE may be associated with obesity.
Material and Method: This study involved genotyping two groups with differing body mass indexes (BMI <or=25 and BMI >or=30) that were composed primarily of middle-age Caucasian subjects (n=421).
Results: The male groups differed significantly in allele frequency at the ACE locus with the I allele more frequent in the BMI >or=30 group (p<0.05). While the female BMI >or=30 group also had a higher I allele frequency than the BMI <or=25 group, the difference is not significant.
Conclusions: Our results demonstrate a sex difference in the association of the I/D polymorphism and BMI. Our findings differ from some other previous studies using various population groups which indicate that the ACE I/D polymorphism may be differentially associated with obesity depending on multiple factors.

Keywords: Peptidyl-Dipeptidase A - genetics, Obesity - physiopathology, Mutation - genetics, Genetic Predisposition to Disease, Gene Frequency, Sex Characteristics, Polymorphism, Genetic, Body Mass Index, Adult