Evaluation of β-Thalassaemia Cases for Common Mutations in Western Rajasthan.

β-Thalassaemia, the most common monogenic disorder, is characterized by genetic heterogeneity at the molecular level. More than 300 mutations of the β globin gene have been characterized all over the world, however, few common mutations account for majority of the cases in various populations. The present study aimed to screen known cases of β-thalassaemia in the Western part of Rajasthan state for five common mutations. The study included 144 known cases of β-thalassaemia of all clinical phenotypes. Cases were diagnosed based on clinical features, haematology investigations including haemogram and Hb-HPLC. Blood samples from cases were taken for mutation analysis. After DNA extraction, mutations were characterized by the polymerase chain reaction method employing allele specific priming technique (AMRS) to study the five mutations including IVS-I-5 (G → C), IVS-I-1 (G → T), CD41/42 (-TCTT), CD 8/9 (+G) and 619 bp deletion from the 3' end of the β-globin gene using a total of seven different primers. Of all 144 cases, 74 (51.38% of all) cases were of β-thalassaemia major, five (3.4% of all) cases were of β-thalassaemia intermedia and 65 (45.14% of all) cases were of β-thalassaemia minor. Mutation analysis revealed that five common mutations were present in 130 (90.27% of all) cases. Among identified mutations, highest frequency of mutation was of IVS-I-5 (G → C) identified in 73 cases (50.7% of all cases). In 11 (7.63% of all) cases, more than one mutation was identified. β-Thalassaemias are common in Western Rajasthan; however, there is dearth of literature from this part of the country. We observed that five common mutations are common in this part of the country also. These observations are helping us in forming the basis for comprehensive diagnostic database that would not only be useful for genetic counselling but also for prenatal diagnosis.