Burden, genotype and phenotype profiles of adult patients with sickle cell disease in Cape Town, South Africa.

BACKGROUND: An exponential increase in the number of sickle cell disease (SCD) patients in paediatric services in Cape Town, South Africa, has been reported. The trend in adult/adolescent services has not been investigated.

OBJECTIVES: To evaluate epidemiological trends of SCD and the profile of patients affected by SCD attending the Haematology Clinic at Groote Schuur Hospital (GSH), Cape Town.

METHODS: (i) A retrospective review of the number of SCD patients over the past 20 years; (ii) a cross-sectional analysis of clinical and haematological characteristics of SCD patients; and (iii) molecular analysis of the haemoglobin S mutation, the haplotype in the β-globin-like genes cluster, the 3.7 kb α-thalassaemia gene deletion and 19 selected single-nucleotide polymorphisms (SNPs) associated with fetal haemoglobin (HbF) levels.

RESULTS: From 1995 to 2016, 81 adolescent/adult patients with SCD were registered, mostly originating from other African countries (n=61, 75.3%). There was an increase of over 200% in new cases (n=47) during the last quarter of the two decades investigated. Data from 34 of 58 regular attendees (58.6%) were analysed. The mean age of the patients was 26.1 years (standard deviation (SD) 9.8), and 70.6% were male. With the exception of four patients with sickle/β-thalassaemia, all the patients had SCD (haemoglobin SS). The co-inheritance of a single 3.7 kb α-globin deletion was found in 42.3% of cases (n=11). The Bantu haplotype was the most observed (65.4% of chromosomes). Most HbF-promoting SNPs were not associated with variable levels of haematological indices.

CONCLUSIONS: There is an increasing burden of adult SCD patients at GSH. National health and academic institutions need to adapt policies and healthcare professional training accordingly.