Science and Education Publishing American Journal of Medicine Studies 2 1 2014 01 06 Genotype and Allele Frequencies of MDR-1 Gene Polymorphism in Jordanian and Sudanese Populations 19 23 EN Abdel Halim Salem Department of Anatomy, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Kingdom of Bahrain Muhalab Ali Amir Ibrahim Mohamed Ibrahim AJMS2014213 10.12691/ajms-2-1-3 2013 12 21 2014 01 02 2014 01 06 The aim of this study was to determine the genotype and allele frequencies of MDR1 gene C3435T polymorphism in Jordanian and Sudanese populations, and to compare them with the frequencies established in various ethnic groups. Genotyping was carried out on 116 unrelated Jordanian and 131 Sudanese subjects. The genotypes of polymorphic position C3435T were determined by PCR-RFLP assay. Results showed that 20.7% of the studied Jordanian subjects were homozygous for the CC genotype, 51.7% were heterozygous for the CT genotype and 27.6% were homozygous for the TT genotype. Among Sudanese subjects, the genotype frequencies were: CC 52.7%, CT 42.0% and TT 5.3%. The frequencies of the 3435T variant in the MDR-1 Gene in Jordanians and Sudanese were found to be 0.534 and 0.263, respectively. According to the distribution of the C3435T SNP, Jordanians were resemble Asians and Europeans but were different significantly from Sudanese, while Sudanese were similar to Africans. In conclusion, the observed distribution of the C3435T SNP in the Jordanian and Sudanese populations was within the range detected in other populations. The data obtained may give the basis for predicting effects of drugs that are substrates for MDR-1 in Jordanian and Sudanese populations and may be useful for individualized therapy of some diseases.