Genetic origin and clinical variability of sickle cell disease in Sri Lanka

Abstract

INTRODUCTION AND OBJECTIVES: Sickle cell disease (SCD) is found at a low prevalence In Sri Lanka. A recent hospital based survey identified 60 patients in the country The clinical spectrum of SCD in Sri Lanka has not been studied and its genetic origin remains unknown.We envisaged to study the genetic origin and to carry out a clinical description ofSCD in Sri Lankan patients. METHODS: Patients were recruited from Ragama, Anuradhapura Hambantota and Kurunegala thalassaemia centres. All patients were examined and clinical details recorded. Genetic analyses were performed to identify the haplotype of HbS, Xmn I polymorphism gene deletions and mutations. RESULTS: A total of 49 SCD patients were studied Ages ranged from 5 - 47 years (mean 20.4) 91.8% of the patients were Sinhalese and the rest were Muslims. 87.7% of the patients had sickle-thalassaemia (SBT) and 6 were homozygous (HbSS) Joint pains were the commonest symptom in patients with SBT Clinical presentations in SBT varied from those with none to frequent crises Clinical management varied with only 42.86% of patients being on hydroxyurea. Most patients had not inherited disease ameliorating genetic factors with 95 9% not having gene deletions and 89 8% not having Hb F up-regulators Three Sickle haplotypes were identified including; Arab• Indian, Benin and Bantu.CONCLUSION: There appears to be at-least three genetic origins of HbS in Sri Lanka SCD is extremely clinically variable in Sri Lanka. The reason for this variation needs further study as most patients seem not to have common inherited modifiers