Y-CHROMOSOMAL SEQUENCES IDENTIFIED IN GONADAL TISSUE OF 2 45,X PATIENTS WITH TURNER-SYNDROME

We examined excised gonadal tissue obtained from two 45, X patients fo r evidence of Y chromosomal material. Both patients had features atypi cal for individuals with Turner syndrome, a large dysgerminoma in pati ent 1 and clitoromegaly in patient 2. Southern blot analysis of polyme rase chain reaction (PCR)-amplified DNA was performed for five Y chrom osome-specific probes (SRY, ZFY, DYZ3, KALY, and DYZ1). Fluorescence i n situ hybridization (FISH) with a combination probe specific for the DYZ1/DYZ3 loci was utilized. For both patients, Southern blot analysis of PCR-amplified DNA with primers for the SRY gene was positive. No s ignals were detected with the other Y chromosome-specific probes for p atient 1. For patient 2, positive signals were obtained for all Y-spec ific probes. FISH was negative in the gonadal specimen from patient 1, while rare cells were positive in the sections from patient 2. Turner syndrome and mixed gonadal dysgenesis may represent different points on a continuum of disorders of sexual differentiation. Although the ri sk for gonadal tumors is considered to be low in patients with Turner syndrome, prospective evaluation is critical to ascertain: The frequen cy of somatic cell mosaicism for cell lines carrying Y chromosomal mat erial, and how the presence of Y chromosomal material in patients with Turner syndrome affects the propensity for virilization and gonadal n eoplasms.