The influence of alpha-thalassaemia on the haematological & clinical expression of sickle cell disease in western India.

We evaluated the clinical and haematological features of 29 sickle cell anaemia patients with associated alpha-thalassaemia and 22 sickle cell homozygotes with a normal alpha-globin genotype from western India. The presence of alpha-thalassaemia resulted in significantly higher haemoglobin (Hb), haematocrit (HCT), red blood cells counts (RBC) and haemoglobin A2 (HbA2) levels but lower mean cell haemoglobin (MCH) and mean cell volume (MCV). The clinical presentation in these patients was also milder with fewer episodes of painful crisis, chest syndromes, infections, requirement of hospitalization and blood transfusions. However, splenomegaly was more common as compared to the patients with a normal alpha-globin genotype. It is evident from the present study that alpha-thalassaemia could be an important genetic factor modulating the clinical expression and haematological severity of sickle cell anaemia in this region.

Prenatal diagnosis of beta-thalassaemia mutations using the reverse dot blot technique.

BACKGROUND: Beta-thalassaemia is the most common genetic disorder among Indians and a number of mutations causing this disease have been reported. Since effective treatment of thalassaemia major is complicated and very expensive, prenatal diagnosis has become an important option for those at risk of having an affected foetus. We report the use of a rapid hybridization method called 'reverse dot blot' for detection of specific mutations of the beta-globin gene. METHODS: DNA was obtained from a 12-week-old foetus by chorionic villus sampling and was amplified using specific primers by the polymerase chain reaction and analysed by the reverse dot blot test. Results were available within 36 hours after sampling. RESULT: The father and mother were found to be heterozygous for codon 15 (G-A) mutation of the beta-globin gene. The foetus was normal. CONCLUSION: Reverse dot blot is a rapid and reliable technique for mutation detection in the beta-globin gene and can be useful for antenatal diagnosis.