SPNS1 is a lysosomal transporter that mediates the salvage of lysoglycerophospholipids, the degradative products of lysosomal phospholipid catabolism. However, an understanding of the role of lysolipid transport and salvage in regulating cellular lipid homeostasis and in disease is lacking. Here, we identified members of 2 families with biallelic SPNS1 loss-of-function variants, who presented primarily with progressive liver and striated muscle injury. Patients’ fibroblasts accumulated lyso...