Polymorphisms in the cytochrome P (CYP) 450 family may cause adverse drug responses in individuals. Cytochrome P450 2C19 (CYP2C19) is a member of the CYP family, where the presence of the 681 G>A, 636 G>A and 806 C>T polymorphisms result in the CYP2C19*2, CYP2C19*3 and CYP2C19*17 alleles, respectively. In the current study, the frequency of the CYP2C19*2, CYP2C19*3 and CYP2C19*17 alleles in an Iranian population cohort of different ethnicities were examined and then compared with previously published frequencies within other populations. Allelic and genotypic frequencies of the CYP2C19 alleles (*2, *3 and *17) were detected using polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis, PCR-single-strand conformation polymorphism analysis and DNA sequencing from blood samples of 1,229 unrelated healthy individuals from different ethnicities within the Iranian population. The CYP2C19 allele frequencies among the Iranian population were 21.4, 1.7, and 27.1% for the CYP2C19*2, CYP2C19*3 and CYP2C19*17 alleles, respectively. The frequency of the homozygous A/A variant of the CYP2C19*2 allele was significantly high and low in the Lur (P<0.001) and Caspian (P<0.001) ethnicities, respectively. However, the frequency of the homozygous A/A variant of the CYP2C19*3 allele was not detected in the Iranian cohort in the current study. The frequency of the heterozygous G/A variant of the CYP2C19*3 allele had the significantly highest and lowest frequency in the Fars (P<0.001) and Lur (P<0.001) groups, respectively. The allele frequency of the homozygous T/T variant of the CYP2C19*17 allele was significantly high in the Caspian (P<0.001) and low in the Kurd (P<0.05) groups. The frequency of the CYP2C19 alleles involved in drug metabolism, may improve the clinical understanding of the ethnic differences in drug responses, resulting in the advancement of the personalized medicine among the different ethnicities within the Iranian population.

Azathioprine therapy was recently used to treat dermatologic conditions such as alopecia areata (AA). Previous reports showed that thiopurine s-methyltransferase (TPMT) activities in human red blood cell are associated with a polymorphism in this gene. Therefore, patients carrying mutant allele of TPMT may show severe myelosuppression when they are treated with standard doses of Azathioprine drugs. This study aimed to evaluate the TPMT gene amongst Alopecia areata patients and healthy adult in Iranian populations. TPMT gene polymorphisms were investigated in 1285 Iranian healthy adult blood donors and 632 patients with Alopecia Areata Universalis (AU). Tetra Arms PCR, Real-Time PCR and Sequencing were used to evaluate the presence of allele-specific polymorphisms of TPMT gene (TPMT *2(c.238 GC,), TPMT *3A (c.460 GA and c.719 AG), TPMT *3B (c.460 GA), and TPMT *3C (c.719 AG). Results were shown that the TPMT*2 allele is associated with a low enzymatic activity that was detected in 22.51% (863 in 1917) of Iranian individuals. Heterozygous genotypes were in 827 (43.14%) subjects (232 AA and 595 healthy), and homozygous genotypes were in 18 (0.94%) individuals (3 AA and 15 healthy). The normal allele (wild-type) was found in 55.92% of the studied individuals (20.70% AA and 35.21% healthy). According to a higher frequency of TPMT polymorphism in Iranian population in comparison with other population, determination of TPMT genotype in may have the clinical benefit to thiopurine dosage selection and treat patients as well.

many forms ranging from a loss in well-defined patches (AA), or diffuse hair loss in the form of total loss of scalp hair called alopecia totalis (AT), or loss of entire scalp and body hair called alopecia universalis (AU), which can affect all hair-bearing sites. Patchy alopecia affecting the scalp is the most common type (