Warfarin pharmacogenetics: polymorphisms of the CYP2C9, CYP4F2, and VKORC1 loci in a genetically admixed Omani population.

This is the first study to evaluate the spectrum and prevalence of dose-predictive genetic polymorphisms of the CYP2C9, CYP4F2 and VKORC1 loci together, in a geographically defined, ethnically admixed healthy adult Omani population sharing common lifestyle/environmental factors. Since the present-day Omani population is the result of an admixture of Caucasian, African and Asian ancestries, we compared the pharmacogenetic profile of these three loci in this population. Interestingly, the Omani pharmacogenetic profile, in terms of allele and genotype distribution, has values that are intermediate between Caucasians and African Americans, the African admixture further substantiated by the presence of the CYP2C9*8 allele. However, limitations and usefulness of such comparisons warrant caution, as the data from pharmacogenetic literature do not always represent bona fide population categories. Furthermore, definition of study population based on microgeographical scale would be more appropriate in pharmacogenetic research rather than the flawed racial, ethnic, or social categorizations since pharmacogenetic variation is clinal, and genetic influences will be further altered by lifestyle and environmental factors.

Forecasting hemoglobinopathy burden through neonatal screening in Omani neonates.

To evaluate the incidence of hemoglobinopathies in Omani subjects and to forecast its future burden on health resources, we initiated a prospective neonatal screening program in two major cities of the Sultanate of Oman. Consecutive cord blood samples from a total of 7,837 neonates were analyzed for complete blood counts and for hemoglobin (Hb) profile by high performance liquid chromatography (HPLC). No case with Hb H (beta4) was detected. We observed that the overall incidence of alpha-thalassemia (alpha-thal) was 48.5% [based on the presence of Hb Bart's (gamma4)] and the beta-globin-related abnormalities accounted for 9.5% of the samples (4.8% sickle cell trait, 2.6% beta-thal trait, 0.9% Hb E trait, 0.8% Hb D trait, 0.08% Hb C trait, 0.3% sickle cell disease and 0.08% homozygous beta-thal). This is also the first large study to establish reference ranges of cord red blood cell (RBC) indices for Omani neonates.

A novel deletional beta-thalassemic variant in an ethnic Qatari patient.

Point mutations are responsible for the majority of the disease-causing alleles in beta-thalassemia (beta-thal) worldwide. We report here a novel deletional variant beta-thal allele in an ethnic Qatari patient, hitherto unreported in the literature. The deletion spans exon 1, the entire intron 1 and the first two bases of exon 2 causing a frameshift and the premature appearance of a stop codon.

Present day inbreeding does not forbid the forensic utility of commonly explored STR loci: a case study of native Qataris.

Allele frequency distribution of 15 short tandem repeat (STR) loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA) was studied in a sample of 120 unrelated native Qatari population using the AmpFISTR Identifiler kit (Applied Biosystems, Foster city, CA, USA). All loci met Hardy-Weinberg expectations and there was no evidence for linkage disequilibrium between any of the marker pairs. The most discriminating locus was D2S1338 with a power of discrimination (PD) of 0.969, while the lowest one was TPOX, yet with a PD of 0.821. For all the 15 loci, the combined PD and the combined power of exclusion (PE) were respectively 0.99999999 and 0.99999744. Thus the probability of finding two individuals bearing an identical 15 locus DNA profile is one in 10(8) native Qatari subjects and this surpasses largely the present day Qatari natives consisting of around 3.5 x 10(5) individuals. The results of this study demonstrate the usefulness and reliability of the AmpFISTR Identifiler kit for individual identification in forensic studies in the native Qatari population, despite the current practice of high inbreeding.

Four tropical, closely related fern species belonging to the genus Adiantum L. are genetically distinct as revealed by ISSR fingerprinting.

The level and pattern of genetic variation was analyzed in four species of the fern genus Adiantum L., A. hispidulum Sw., A. incisum Forrsk., A. raddianum C.Presl, and A. zollingeri Mett. ex Kuhn, originating from South India, using the ISSR fingerprinting method. The populations of Adiantum possessed a considerable level of genetic variation, the diversity indices ranging from 0.284 to 0.464. Only 12% of the ISSR markers found were restricted to one species only, and 54% were detected in all four species. The analysis of molecular variance revealed that 71.1% of variation was present within populations. The proportion of variation detected among species was only 18.5% while the proportion of variation among populations within species equalled 10.4%. Despite the low level of intrageneric differentiation, the discriminant analysis and clustering of genetic distances indicated that the four Adiantum species are genetically distinct. The F(ST) values calculated for the species were low, varying from 0.089 to 0.179. No linkage disequilibrium was detected between the loci. Such low level of differentiation among populations and the presence of linkage equilibrium reflect that the life history of Adiantum ferns apparently involves common or relatively common sexuality, effective wind-dispersal of spores and outcrossing.