Several studies have shown that the cRNA of human, rabbit, or rat rBAT induces in Xenopus oocytes sodiumindependent, high affinity uptake of L-cystine via a system b 0,؉ -like amino acid exchanger. We have shown that mutations in rBAT cause type I cystinuria (Calonge, M. J., Gasparini, P., Chillaró n, J., Chilló n, M., Gallucci, M., Rousaud, F., Zelante, L., Testar, X., Dallapiccola, B., Di Silverio, F., Barceló , P., Estivill, X., Zorzano, A., Nunes, V., and Palacín, M.