GPD1L is converts sn-glycerol 3-phosphate to glycerone phosphate. This protein is found in the cytoplasm, associated with the plasma membrane, where it binds the sodium channel, voltage-gated, type V, alpha subunit (SCN5A). GPD1L is thought to affect trafficking of the cardiac sodium current to the cell surface. Mutations in GPD1L are the cause of sudden infant death syndrome (SIDS) and Brugada syndrome type 2, an autosomal dominant tachyarrhythmia.