Increased frequency of angiotensin-converting enzyme DD genotype in Saudi overweight and obese patients

Several studies have been carried out to investigate the insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) in obese and normal weight individuals, often with contradictory results in different populatios. In some studies, the DD genotype occurs at a high frequency in obesity, while in others no association has been demonstrated. Since obesity and overweight are of frequent occurrence in the Saudi population, we initiated this study to investigate the I/D polymorphism of ACE in obese, overweight and normal weight Saudis.

The study group included 457 Saudi males and females. The height and weight were measured and body mass index (BMI) was calculated. Based on the BMI value, the total study population was classified as normal, overweight and obese. A total of 117 obese (BMI >30 (kg/m(2))), 185 overweight (BMI=25-29.9 (kg/m(2))) and 155 normal weight individuals (BMI< (kg/m (2)) were enrolled. Polymerase chain reaction (PCR) and agarose gel electrophoresis were used to study the ACE polymorphism. For the deletion (D) form, a 190 bp and for the insertion (I) form, 490 bp DNA fragment were obtained on 2% agarose gel electrophoresis.

The frequency of DD genotype was 76.9% in the obese, and 73.5% in the overweight individuals, compared to 19.66% and 24.86% of the ID genotype in the obese and overweight, respectively. Among the normal weight individuals, the frequency was significantly lower for DD and higher for the ID genotype, i.e., 58.7% for DD and 40% for ID. The allele frequencies in the obese were 0.867 and 0.133 for the D and I alleles, respectively. While in the overweight, the frequencies were 0.859 and 0.141 for these alleles, respectively, compared to 0.787 and 0.213 in the normal weight individuals.

The DD genotype and D allele occur at a high frequency in Saudi overweight and obese individuals, and may have some role in fat accumulation by affecting metabolic pathways of fat, thus leading to the development of overweight and obesity.