An infant with ambiguous genitalia was found to have a karyotype 45,X/46,X,r(Y)(p11.2;q11.23)/47,X, idic(Y)(p11.2),idic(Y)(p11.2) using G-banding, C-banding and FISH. Examination of the genitalia revealed a phallus measuring 1.5 cm in length and 0.5 cm wide with perineal orifice. Subtle phenotypic features consistent with Turner syndrome were not present. Genital ultrasonography revealed the presence of an infantile uterus. Endoscopy of the vagina, uterus and cervix appeared normal. (C) 2001 Editions scientifiques et medicales Elsevier SAS.