CASP9 and chronic kidney disease: In a GWAS analyzing molecular insights into chronic kidney disease-defining traits, Xu et al. [20] reported the causal effects of three genes (NAT8B, CASP9, and MUC1) on the eGFR, identified rs4072037 as a common alternative splice variant in MUC1, and observed increased renal expression of a specific MUC1 mRNA isoform as a plausible molecular mechanism underlying the GWAS association signal.