As reported by Broer, both renal and intestinal LPI phenotypes are explained by the presence of the sole system y+L transporter in the basolateral membranes of these tissues 17; indeed, the lack of a functional y+LAT1 consequent to SLC7A7 mutations is realistically the reason for the impaired absorption‐reabsorption of cationic amino acids, and, in turn, for the low plasma levels of arginine and other cationic amino acids in LPI patients. The gene discussed is SLC7A7; the disease is lysinuric protein intolerance.