Molecular genetic diagnosis of Glanzmann syndrome in Iranian population; reporting novel and recurrent mutations.

BACKGROUND: Glanzmann thrombasthenia (GT) is a rare autosomal recessive abnormality of platelet aggregation with quantitative and/or qualitative abnormality of αIIbß3 integrin. The αIIbß3 is a platelet fibrinogen receptor, which is required for platelet aggregation, firm adhesion, and also spreading. The disease is more prevalent in the populations with a higher rate of consanguineous marriages as in some Middle Eastern populations including Iraq, Jordan, and Iran. Different types of mutations in ITGA2B and ITGB3 genes have been previously reported to cause the disease. RESULT: In this study, 16 patients with the clinical diagnosis of GT were studied. Direct sequencing of the exons and exon-intron boundaries of the above genes revealed mutations in 14 patients (detection rate: 87.5%). Briefly, out of fifteen types of identified mutations, 14 were novel. Seven mutations in the ITGB3 gene included 4 missense [c.2T > C, c.155 G > T, c. 538 G > A, c.1990 G > T], one nonsense mutation [c.1303 G > T], a small deletion [c.1656_1658delCTC] and a deletion of one nucleotide [c.401delA]. Mutations in the ITGA2B were 8 different mutations consisting 2 missense [c.286 T > A, c.842 C > T], 2 deletions [c.1899 del T, c.189-319_236del], an insertion [c.1071_1072insG] and one splice site mutations [c.409-3 C > G], one synonymous mutation that might alter the normal splicing process [c.1392 A > G] and a nonsense mutation [c.1555 C > T]. The causative mutation in 2 patients remained unknown. Using long-range PCR and sequencing, we found a rather large deletion. The break point of this deletion covers 319 nt from the last part of the first intron and 48 nt from the beginning of the second exon of ITGA2B gene. The deletion was also detected in two unrelated patients with the same ethnicity. In addition, in silico analyses of novel mutations were performed. CONCLUSION: There was no recurrent mutation in the studied population. This may be due to either small sample size or the heterogeneity of the studied population.

Th-1 cytokines gene polymorphism in human brucellosis.

Brucellosis is a worldwide zoonosis. Infection with Brucella species results in the activation of cell-mediated immune response. The interaction between Th1and Th2 cytokines determines the outcome of disease. Production of each cytokine is in turn affected by genetic factors. In this study, we investigated the possible association between Th1 cytokines gene polymorphism and brucellosis. Different genotypes of TNF-alpha, IFN-gamma and IL-2 were determined by polymerase chain reaction-sequence-specific primer in 47 patients with brucellosis and in 166 healthy controls. Allele frequencies of these genotypes were compared using the chi2 test. The results showed a significant difference in the TNF-alpha genotype GG/GG in patients in comparison with controls (76.7% vs. 21%) (P = 0.001, OR = 12.42, 95%CI 5.7-27.7). There was no significant difference in the frequency distribution of the IFN-gamma genotypes between two groups. IL-2 GG genotype at position -330 was about two times more common in cases than in controls, but the difference was not significant (10.6 vs. 4.6 P value = 0.09). This study shows that genetically low producers of TNF-alpha are possibly susceptible to brucellosis and raise doubt about the role of gene polymorphism of INF-gamma in brucellosis which was demonstrated in previous studies. It seems that patients with brucellosis did not have a defect in producing IL-2 with even a trend towards producing higher amounts of this cytokine.