Ullrich-Turner syndrome: seven pregnancies in an apparent 45,X woman.

A 37-year-old woman was referred for genetic counseling after termination of her probable seventh pregnancy. Ultrasound examination at 13 weeks of gestation had shown a fetus with bilateral cystic hygromas. A transabdominal amniocentesis confirmed 45,X karyotype in the fetus. The patient had marked short stature and a 45,X chromosome constitution in blood lymphocytes. Subsequently she had a hysterectomy and oophorectomy. Tissue of representative sites of the pathological specimen showed a 45,X chromosome constitution. However, molecular analysis of 8 sites from the uterus and ovaries, and of skin fibroblasts with X-chromosome microsatellites showed the presence of only one allele, except for the microsatellite DXS996 which demonstrated 2 alleles (155 bp and 161 bp) in ovarian tissue. The lymphocytes from the mother and her only son demonstrated the same single allele (161 bp). We conclude that molecular analysis of lymphocytes and of tissue is necessary for detecting low-level mosaicism in apparently homogeneous 45,X women.