What is BCRABL gene mutation is seen in? and explain in detail?
Ans. is 'a' i.e., CMLChronic Myeloid leukemiao Chronic myeloid leukemia is a stem cell disease that is characterized by leucocytosis with granulocytic immaturities, basophilia, splenomegaly and distinct chromosomal abnormality - Philadelphia (Ph') chromosome. It is one of the chronic myeloproliferative disorders.Pathogenesis of chronic mveloid leukemiao CML is an acquired disease of haemopoietic stem cell and Ph' chromosome is demonstrable in erythroid, myeloid and megakaryocytic precursors.Philadelphia chromosome BCR-ABL fusion genePhiladelphia chromosome is formed as a result of reciprocal translocation between long arm of chromosome 22 and chromosome 9 i.e. + (9:22)ABL proto-oncogene from chromosome 9 is translocated to chromosome 22 where BCR is present and results in formation of BCR-ABL fusion chimeric geneBCR ABL gene is hallmark of CML.Diagnostic criteria for CMLChronic phaseAccelerated phase (one or more of following)Blast phase (one or more of following )o t (9:22)/bcr-abi transcriptso <10% blasts in blood or bone marrowo 10-19% of blasts in blood or marrowo 2: 20% of peripheral blood basophilso Thrombocytopenia unrelated to treatmento Leukocytosis or splenomegaly unrelated to treatmento Cytogenetic evidence of clonal evolutiono >20% blasts in blood or bone marrowo Extramedullary' blast proliferationo Clusters of blasts in bone marrow biopsy (1Vote:- 2/3 blasts are myeloid, 1/3 are) lymphoid)o Two index have been decribed for prognosis of CMSokal index : It includes% of circulating blastsPlatelet countAgeSpleen sizeCytogenetic clonal evolution.Hasford system : It includes : -% of circulating blasts% of basophils & eosinophilsPlatelet countSpleen sizeAge