Mapping these 18 genes to a comprehensive human Protein-Protein Interaction (PPI) network (Wu et al., 2009; Mazandu et al., 2018), we identify sub-networks containing these gene variants: APOL1, SYPL2, WNT7A, IGFBP5, UNCX, NFKB1, UMOD, and SKIL. Three gene variants within this sub-network, namely APOL1 (G1)-rs73885319, as well as APOL1 (G2)-rs71785313, WNT7A-rs6795744, and SYPL2-rs12136063, have been identified to influence variation in renal dysfunction phenotypes in SCD patients. The gene discussed is IGFBP5; the disease is Schnyder corneal dystrophy.