NAAA and chronic kidney disease: Transcriptomic analysis of kidney biopsies from patients with chronic kidney disease (CKD) further uncovered coordinated remodeling of sphingolipid metabolism genes, with increased expression of ceramidases (ASAH1 and NAAA) and downregulation of ceramide synthases (CERS4, CERS5), consistent with adaptive regulation of the Cer/CerK/C1P axis.