Given this noted superior performance of GFRNMR in adults with and without CKD, this multicenter retrospective study sought to compare the performance of GFRNMR with that of CKD-EPI equations based on creatinine only [eGFRcr(ASR), eGFRcr(AS)] or on both creatinine and cystatin C [eGFRcr-cys(ASR), eGFRcr-cys(AS)], against mGFR as reference standard, in 205 patients with CLD. The gene discussed is CST3; the disease is congenital secretory chloride diarrhea 1.