LPI is caused by mutations in the SLC7A7 gene (solute carrier family 7, member 7) encoding y + LAT‐1 protein, the catalytic light chain subunit of the heteromeric amino acid transporter located at the basolateral membrane of the epithelial cells of the renal proximal tubules and intestine. Here, SLC7A7 is linked to lysinuric protein intolerance.