The same study reported a urinary excretion of 15–51 μmol/24 h for L-homoarginine in cystinuria patients, as compared to 1–6 μmol/24 h in controls [18], indicating that L-homoarginine reabsorption from the urine is mainly mediated by b0,+AT-rBAT. This evidence concerns the gene SLC3A1 and cystinuria.