Predictive factors of severity in sickle cell disease (SCD)

The level to which SCD clinically manifests itself can vary significantly:

• HbSS and HbS/ beta thalassaemia display greatest severity
• severity of sickling depends on the percentage of haemoglobin present

Several genetic and environmental factors may affect the severity of sickling in an individual:

• genetic factors
  • a higher than usual HbF level
  • coexisting thalassaemia
  • double heterozygosity (e.g. - HbSC)
  • other linked genetic polymorphism leading to severe or mild phenotypes
• environmental factors - infection, climate, nutrition, psychosocial factors, socioeconomic status

Reference

1. Bain BJ, Daniel Y, Henthorn J, et al. Significant haemoglobinopathies: a guideline for screening and diagnosis: a British Society for Haematology guideline. Br J Haematol. 2023 Jun;201(6):1047-65.