Phenotypic expression of tissue mosaicism in a 45,X/46,X,dicY(q11.2) female

We describe a girl who presented at the age of 11 years with short stature. She had female external genitalia and some clinical features of Turner syn drome. At laparotomy a uterus and Fallopian tubes and small gonad-like tiss ue masses in the region of the Fallopian fimbria were found. The tissue mas ses were removed and histological examination revealed no organized testicu lar or ovarian morphology. Remnants of Fallopian tubes, epididymis, and clu sters of Leydig cells were seen but no Sertoli cells were found. Endocrine studies showed levels of sex hormones consistent with primary gonadal failu re. G-banding analysis of 16 blood lymphocytes revealed the karyotype 46,X, dicY(q11.2) in all cells. Varying proportions of X and Y centromeres in blo od lymphocytes, skin fibroblasts, and in the incompletely formed Wolffian a nd Mullerian duct derivatives were demonstrated by FISH. Molecular studies confirmed the absence of most of the long arm of the Y chromosome and an in tact short arm. The SRY gene was shown to be present, but we presume that d ue to the mosaicism the dose was insufficient to allow normal testicular de velopment. (C) 2001 Wiley-Liss, Inc.