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DNA haplotypes in Africans and West Indians with sickle cell anaemia or SC disease
K Konstantopoulos1, T Vulliamy, D Swirsky
1Department of Haematology, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
Insights
Genetic variations in sickle cell disease (SCD) were studied. The beta globin haplotype, particularly the Benin type, was common but unlikely to determine clinical severity in London patients.
Area of Science:
- Genetics
- Hematology
- Molecular Biology
Background:
- Sickle cell disease (SCD) is a genetic blood disorder.
- Genetic variations, including beta globin cluster haplotypes, may influence SCD's clinical presentation.
Purpose of the Study:
- To analyze beta globin cluster haplotypes in SCD patients.
- To investigate the association between haplotypes and clinical severity in a London-based population.
Main Methods:
- Haplotype analysis of the beta globin cluster was performed.
- Data collected from 47 patients with sickle cell disease (33 SS, 1 S/beta thal(0), 13 SC).
Main Results:
- The Benin haplotype was predominant (82.5%) among tested chromosomes.
- The Bantu-A4 haplotype was common on C chromosomes (85%).
- New haplotypes (E, H, O) were identified in a minority of patients.
Conclusions:
- The beta globin haplotype is unlikely to be a major determinant of clinical severity in this SCD patient cohort.
- The predominance of the Benin haplotype suggests a common ancestral origin for many cases.
Abstract:
Considering that genetic variation linked to the beta S mutation may influence the clinical manifestations of sickle cell disease, we have analyzed the beta globin cluster haplotypes in 47 patients with this condition (33 SS homozygotes, one S/beta thal (0), and 13 SC) living in London (30 West Indian, 17 West African). Of the 80 chromosomes tested, 82.5% had the Benin haplotype and of the 13 C chromosomes tested, 85% had the Bantu-A4 haplotype. A minority of patients had Bantu or Senegal haplotypes, and in 5 patients we found new haplotypes called E, H and O which may have arisen through mutation or recombination. Because of the predominance of a single haplotype (Benin) nearly all our homozygous S patients were either homozygous or heterozygous for this haplotype. We concluded that the beta globin haplotype is unlikely to be an important determinant of the clinical severity in this patient population.