Mild-phenotype sickle cell disease: molecular basis, clinical presentation and management recommendations

Summary 

Although sickle cell disease (SCD) is monogenic, its clinical presentation is highly heterogeneous. Many of the modulating factors are genetically determined while others are environmental. The β-globin gene haplotype, level of fetal haemoglobin and co-inheritance of α-thalassaemia trait are some of the genetic factors. Many SCD patients in the Arabian Peninsula have the Arab/India haplotype and are characterized by elevated Hb F levels. They tend to have a mild phenotype, presenting with fewer pain episodes and less anaemia. Stroke, leg ulcers, acute chest syndrome, priapism and early splenic dysfunction are uncommon. Management of acute episodes does not differ from usual recommendations, but the use of routine penicillin prophylaxis to prevent pneumococcal sepsis may not be mandatory.

Keywords: Sickle cell disease, Hb F, Arab/India haplotype, α-thalassaemia trait