Allele and genotype frequencies of polymorphic DCP1, CETP, ADRB2, and HTR2A in the Egyptian population

Objective: The goal of this study was to determine the frequencies of important allelic variants of two drug targets, dipeptidyl carboxypeptidase (DCP1) and cholesteryl ester transfer protein (CETP), and two other drug receptors, beta-2 adrenergic receptor (ADRB2) and 5-hydroxy tryptamine 2A receptor (HTR2A), in the Egyptian population and compare them with the frequencies in other ethnic populations. Methods: A sensitive real-time polymerase chain reaction assay was developed and successfully applied for genotyping of the consensus (wild-type) alleles plus five variants of four genes: DCP1 [the insertion allele (I) versus the deletion allele (D)], CETP*TaqI (B1 versus B2), ADRB2*R16G, ADRB2*Q27E, and HTR2A*102T>C. This study was carried out in 242 unrelated Egyptian subjects and is the first to describe these allelic variants in the Egyptian population. Results: The frequencies of the tested alleles were found as: DCP1 (I:D, 0.32:0.68), CETPTaqI (B1:B2, 0.65:0.35), ADRB2*R16G (Arg16:Gly16, 0.57:0.43), ADRB2*Q27E (Gln27:Glu27, 0.76:0.24), and HTR2A*102T>C (T102:C102, 0.53:0.47). The common Arabian ancestors of the Egyptians, Spanish, Saudi, and Emirate had created a common pattern of distribution of some allelic variants (DCP1 and CETP). However, in the genotyping of ADRB2, the frequency of the polymorphism at codon 16 was found to be similar to the Chinese population, whereas that at codon 27 was similar to African-Americans with significant differences than other Caucasian populations. The frequency of the HTR2A*102T>C variant appeared to be similar to many Caucasian populations and African-Americans. Conclusions: We have explored the frequencies of important allelic variants DCP1, CETP, ADRB2, and HTR2A among the Egyptian population focusing on the ethnic diversity in the distribution of the tested mutant alleles. Our results may help in better understanding the observed ethnic variation in angiotensin-converting enzyme inhibition and atherosclerosis therapy. It also may contribute to better characterization of interethnic differences in isoprenaline and clozapine response, which will have implications for the cost effective and rational prescribing of these drugs.