Study of IRF-8 gene in Kashmiri population and its relation with Chronic Myeloid Leukemia

Chronic myelogenous leukemia (CML) is a clonal hematopoietic disorder caused by an acquired genetic defect in a pluripotent stem cell. A number of theories have been postulated to describe the etiology of CML such as genetic alterations and alterations in cytokine production. A combination of inflammatory cytokines have an important role in cancer development. The aim of this study was to screen for mutations of IRF-8 gene in CML cases and healthy controls of the Kashmiri population. We included eighty confirmed CML cases and an equal number of age, district and gender matched controls in this study. HaeIII enzyme digestion cuts amplified product at 5’-GGCC-3’ sequence and any mutation in it abrogates restriction digestion by this enzyme. Restriction results showed wild conditions with no mutation at any of the 6 positions where HaeIII cuts, which was confirmed by the sequencing results as well. Further sequencing results showed interesting single G A substitution at position 92 of the amplified product. In CML cases, the allelic frequency for normal allele (G) was found to be 47.5% (76/160) and the allelic frequency observed for G A type was found to be 52.5% (84/160). The allelic frequency observed in controls for normal allele (G) was 91.25% (146/160). The frequencies analyzed for G A allele was 8.75% (14/160). Since the frequency observed for G A allele was higher in CML cases (52.5%) than in normal controls (8.75%) and it was found to be statistically significant (OR= 11.52, 95%CI: (6.13-21.6); p = 0.001). Sequencing results further showed occasional deletion at the same position where transition was seen. Also we found that CML is prevalent more in males as compared to females (ratio is 1:1.12). Majority of the CML case were from district Srinagar of the Valley. Mean age of the cases and controls were found to be 44.7 years and 43.6 years respectively. We observed a higher representation of CML cases in the age group between 30 and 40. Furthermore, the presence of the Philadelphia chromosome (BCR-ABL fusion gene) was observed in 82.5% of CML cases in our study. This is the first report of the sequence variation in exon 7 region of IRF-8 gene and the risk to CML in the Kashmiri population. However, more insight need to be gained and further substantiated by conducting a similar study on statistically significant sample size