APOL1 Renal Risk Variants and Sickle Cell Trait Associations With Reduced Kidney Function in a Large Congolese Population-Based Study

INTRODUCTION: APOL1, GSTM1 risk variants, and sickle cell trait (SCT) are associated with chronic kidney disease (CKD) among African Americans (AAs). Nevertheless, such evidence remains scarce in sub-Saharan Africa (SSA) populations. METHODS: In a cross-sectional study, we evaluated the prevalence of these risk variants and their association with estimated glomerular filtration rate (eGFR), albuminuria, and CKD in urban (n = 587) and rural (n = 730) adults from South-Kivu, DR Congo (DRC). Furthermore, we evaluated APOL1 recessive model (high risk [HR] vs. low risk [LR]), SCT carriage, and the active versus inactive GSTM1 genotypes. RESULTS: The frequencies of the APOL1 G1 and G2 alleles were 8.7% and 9.1%, respectively, and 3.2% carried the HR genotype. SCT and GSTM1 null allele frequencies were 3.8% and 51.2%, respectively. APOL1 HR was associated with lower eGFR (P = 0.047, odds ratio [OR] = 4). Individuals with SCT exhibited lower eGFR (P = 0.018), higher albuminuria (P = 0.032), and 2.4× increased risk of CKD (P = 0.031). APOL1 HR and SCT were synergistically associated with lower eGFR (P(interaction) = 0.012). The GSTM1 null allele was not significantly associated with any renal outcomes. CONCLUSION: Our study highlighted the impact of APOL1 and SCT variants on poorer renal outcomes in the DRC and advocates for further genetic studies in SSA settings.