Spectrum of β-thalassemia mutations in North Indian states: A β-thalassemia trait with two mutations in cis

Objectives: To study the prevalence of β-thalassemia mutations in two North Indian states. Design and methods: Mutation(s) were analyzed in 62 patients using 10 sets of allele-specific primers. Results: Four mutations [IVS1 nt5 (G → C), F.S 8/9 (+G), F.S 41/42 (−TCTT) and del 619 bp] were found to constitute 94.1% of the total alleles studied. Prevalence of IVS1 nt5 (G → C) was the highest, closely followed by F.S 8/9 (+G). The latter was thus unusually high and not consistent with earlier reports. Two mutations in cis were detected in one carrier of the thalassemia trait and in his father, thus signifying the possibility of vertical transmission of mutations in a single β-globin allele. Conclusions: F.S 8/9 (+G), as well as IVS1 nt5 (G → C), are the major mutations in Indian states; however, the possibility of multiple mutations in cis in a fetus with the thalassemia trait has to be considered in a prenatal screening program.