Objectives
To explore putative associations between specific variants in either the glutathione S‐transferase (GST), haptoglobin (HP) or uridine 5′‐diphospho‐glucuronosyltransferase 1A1 (UGT1A1) genes and clinically important phenotypes in sickle cell anaemia (HbSS).
Methods
371 HbSS participants were recruited from the Sickle Cell Clinic of the Sickle Cell Unit at the University of the West Indies, Kingston, Jamaica. Markers within four GST superfamily genes, the HP gene and the UGT1A1 gene were analysed using PCR‐based assays.
Results
Multivariable regression revealed statistically significant associations between the GSTP1 Ile105Val heterozygote and HbA2 levels (P = .016), HbF percentage (P = .001), MCH concentration (P = .028) and reticulocyte count (P = .032), while the GSTM3 D/D homozygote was significantly associated with HbA2 levels (P = .032). The UGT1A1 (TA)6/(TA)8 heterozygote showed statistically significant associations with HbA2 levels (P = .019), HbF percentage (P < .001), haemoglobin levels (P = .008), PCV values (P = .007) and RBC counts (P = .041).
Conclusion
This exploratory cross‐sectional study has generated novel and informative genotype‐phenotype estimates of association, but larger studies are needed to determine whether these specific variants within the GST, UGT1A1 and HP genes are related to interindividual phenotypic variability in HbSS.