Pattern of hemoglobinopathies and thalassemias in upper Assam region of North Eastern India: High performance liquid chromatography studies in 9000 patients

Background: The hereditary hemoglobin (Hb) disorders are the most commonly encountered single gene disorders in India. Data pertaining to the pattern of hemoglobinopathies and thalassemias is scarce in North East India, and hence it was considered worthwhile to study these disorders using a large series of patients referred to a clinical diagnostic laboratory. Aims: A total of 9000 patients referred for Hb variant analysis were studied to identify hemoglobinopathies and thalassemias in Upper Assam region of North East India. Materials and Methods: This study was performed by high performance liquid chromatography (HPLC) using BIORAD variant Hb typing system. Results: Out of 9000 patients studied, abnormal Hb fractions were seen in 5320 patients. The HbE gene was detected in 4315 patients of which HbE trait was seen in 2294 followed by HbE disease in 1892. There were 114 HbE beta thalassemia patients and 15 double heterozygotes of HbE with HbS or HbD. Beta thalassemia trait was seen in 313 patients and beta thalassemia homozygous in 32. HbS gene was detected in 460 patients comprising of HbS trait in 189, HbS disease in 203, S beta thalassemia in 53 and double heterozygotes of SD and ES in 15. The rest comprised of HbD trait in 6, delta beta thalassemia in 33, hereditary persistence of fetal hemoglobin trait in 5 and J chain hemoglobinopathy in 8 patients. Evidence of alpha thalassemia though suspected, could not be confirmed. Conclusion: A high incidence of hemoglobinopathies and thalassemias and their combinations is unique for this part of the country