45,X/46,XY Mosaicism: Clinical management and Counseling Issues

Individuals with 45,X/ 46,XY mosaicism can present variant phenotypes ranging from normal appearing males to females with the clinical manifestations of Turner Syndrome. In males, hypospadias, undescended testis, and Muellerian remnants are quite common. In all individuals with 45X/46,XY, mosaicism, the risk of gonadal malignancies is increased. In order to prevent complications associated with gonadal dysgenesis we recommend routine testicular biopsies in newly diagnosed male patients, and routine follow up with pediatric urologists in all patients. We report two new cases of 45,X/46,XY and discuss the clinical and counselling issues involved.