MBTPS1 and nephrotic syndrome 14: While the underlying pathomechanism of SPLIS nephropathy remains incompletely understood, a large body of evidence supports the role of S1P signaling in fibrosis of the lung, liver, heart and other tissues (Zhang et al., 2018; Zhao et al., 2018; Shea and Tager, 2012; Huwiler and Pfeilschifter, 2018; Wang et al., 2018).