Differences in the frequency of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene among the Lebanese population.

In view of its role in precipitating mild hyperhomocysteinemia as well as being a risk factor for vascular thrombosis, we investigated the frequency of the C677T mutation of the methylenetetrahydrofolate reductase (MTHFR) gene among 589 healthy Lebanese subjects by PCR-RFLP analysis (HinfI digestion) and compared them with those of other countries of Caucasian and non-Caucasian origin. The prevalence of the mutated homozygous (T/T) and heterozygous (C/T) C677T MTHFR genotype was 11.04% and 39.73%, respectively, giving an allele frequency of 0.309. While the prevalence of the T/T genotype was similar with respect to gender, higher prevalence was noted among Christian (13.08%) compared to Moslem (7.66%) subjects (P < 0.001), and heterogeneity in its distribution was seen in the different Lebanese provinces, and was directly related to the Christian/Moslem composition of each province. The distribution of the MTHFR C677T in Lebanon is unique with regard to its higher occurrence among Christians compared to Moslems, adding to the existing body of literature on the heterogeneity of its prevalence and distribution.

Prevalence of hepatitis C virus isolate genotypes from chronically infected Lebanese patients: a hospital-based study.

To assess percentages of hepatitis C virus (HCV) genotypes in infected Lebanese patients referred to St. George Hospital, Beirut, Lebanon, 77 infected cases were studied. Of those, 27 were hemodialysis patients. Genotyping was performed by nested PCR of the HCV core-region with specific primers, followed by DNA enzyme-immunoassay using HCV type and subtype-specific probes. Single genotype infections were detected in 52 patients (67.5%). In these cases, types 1, 2, 3 and 4 were detected in 19.5%, 32.5%, 5.1% and 10.4% of the cases respectively. Twenty-five (32.5%) samples showed mixed genotype infections. Single genotype distribution was significantly different among dialysis and non-dialysis patients. In the dialysis group, genotype 2 was predominant (80%, p < 0.001). In single HCV genotype-infected patients, subtype 1b was frequently detected in nondialysis cases (34.4%) whereas this genotype was found in only 5% of dialysis cases. Genotypes 5 and 6 were not detected in any of the cases studied. This pilot hospital-based study provides evidence for the diversity of HCV genotypes in the Lebanese population and establishes differences in distribution depending on the risk group.