Fetal Haemoglobin and β-globin Gene Cluster Haplotypes among Sickle Cell Patients in Chhattisgarh

Foetal Haemoglobin (HbF) is the best-known genetic modulator of sickle cell anaemia, which varies dramatically in concentration in the blood of these patients. The patients with SCA display a remarkable variability in the disease severity. High HbF levels and the β-globin gene cluster haplotypes influence the clinical presentation of sickle cell disease. To identify the genetic modifiers which influence the disease severity, we conducted a β-globin haplotype analysis in the sickle cell disease patients of Chhattisgarh.

The foetal haemoglobin and the β-globin gene haplotypes of the sickle cell trait and the sickle cell disease patients from Chhattisgarh were investigated.

A total of 100 sickle cell patients (SS), 50 sickle cell trait patients (AS) and 50 healthy control individuals were included in the present study. The distribution of the β-globin gene haplotype was done by the PCR-RFLP method.

PCR-RFLP showed that the homozygous Arab-Indian haplotype (65%) was the most frequent one, followed by the heterozygous Arab-Indian haplotype (11%) in the sickle cell patients (SS), while the AS patients had a higher frequency of the heterozygous Arab-Indian haplotype (38%) in comparison to homozygous one (32%). Four atypical haplotypes, 3 Benin and 1 Cameroon were also observed, although they were in lower frequencies. In the present study, the HbF levels were higher in the AS and the SS patients, with one or two Arab-Indian haplotypes as compared to the other haplotypes.

The presence of the Arab-Indian haplotype as the predominant haplotype might be suggestive of a gene flow to/from Saudi-Arabia or India and it was associated with higher HbF levels and a milder disease severity.