Prevalence of various mutations in beta thalassaemia and its association with haematological parameters.

OBJECTIVE: To determine the prevalence of various mutations in beta (beta) thalassaemia and its association with haematological parameters. METHODS: A descriptive cross sectional study was carried out in the Department of Haematology, Armed Forced Institute of Pathology (AFIP) from February 2009 to January 2010. A total of 515 carriers having beta thalassaemia mutations characterized by Multiplex amplification refractory mutation system (ARMS) were included in the study. Frequencies of different beta thalassaemia mutations were calculated. Mutations were analyzed for their haematological parameters which include total red blood cell count (TRBC), haemoglobin (Hb), mean cell volume (MCV), mean cell haemoglobin (MCH) and red cell distribution width (RDW). RESULTS: Frame shift (Fr) 8-9 was the most common mutation found in 183 (35.5%) of patients followed by intervening sequence 1-5 (IVSI-5) in 126 (24.5%) and Fr 41-42 in 76 (14.8%) while IVSII-1 was the least common mutation found in 1 patient. Fr 8-9 was also the commonest mutation in Punjabis and Pathans. Predominant mutation in other ethnic carriers was IVSI-5. Patients with Fr 8-9 mutation had the lowest mean MCV and MCH of 63.7fl and 19.1pg, of all the mutations. Patients with CAP+1 mutation had mean TRBC, Hb, MCV, MCH and RDW of 5.5 x 1012/L, 13.5g/dl, 78.0fl, 24.7pg and 41.9fl respectively. CONCLUSION: Fr 8-9 is the most common beta thalassaemia mutation with lowest red cell indices while CAP+1 mutation can present with normal red cell values therefore, a potential carrier should be screened for CAP+1 mutation by DNA analysis.

Frequency of Janus associated kinase 2 (V617F) mutation in patients of polycythemia vera.

OBJECTIVE: To determine the frequency of Janus associated kinase 2 ( JAK2) mutation in patients of polycythemia vera (PV). STUDY DESIGN: Descriptive cross-sectional. PLACE AND DURATION OF STUDY: Haematology Department, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from January 2008 to December 2009. METHODOLOGY: Forty-six consecutive patients of PV diagnosed by the conventional haematological criteria were included in the study. Blood samples of all patients were screened for G-T point mutation (V617F) in the JAK2 gene on chromosome 9 by an allele specific polymerase chain reaction (PCR). RESULTS: JAK2 V617F mutation was found in 43 out of 46 patients (93.5%) with PV. Among them, 30 were males (65.2%) and 16 were females (34.8%). Mean TLC in patients with PV was 16.5 ± 9.1 x 109/L, mean haemoglobin (Hb) was 17.8 ± 2.0 g/dl, mean platelet count was 531 ± 261 x 109/L, mean PCV was 57.9 ± 6.3 l/l, mean MCV was 78.8 ± 11.0 fl and mean MCH was 24.4 ± 4.8 pg. CONCLUSION: Peripheral blood mutation screening for JAK2 V617F can be incorporated into the initial work up of patients suspected to have polycythemia as this mutation is present in majority of such patients.