Severe nonspecific x-linked mental retardation caused by a proximally xp located gene: intragenic heterogeneity or a new form of x-linked mental retardation? - Passos-Bueno, Maria Rita; Byth, B C; Rosemberg, Sérgio; Takata, R I; Bakker, E; Beggs, A H; Pavanello, R C M; Vainzof, Mariz; Davies, K E; Zatz, Mayana (American Journal of Medical Genetics, 1993)