Turner syndrome
Gonadoblastoma is most often associated with an abnormal chromosomal karyotype, gonadal dysgenesis, or the presence of a Y chromosome in over 90% of cases. Gonadoblastoma has been found in association with androgen insensitivity syndrome, mixed gonadal dysgenesis and Turner syndrome, especially in the presence of Y chromosome-bearing cells. Women with Turner syndrome whose karyotype includes a Y chromosome (as in 45,X/46,XY mosaicism) are at increased risk for gonadoblastoma. Because of the risk of gonadoblastoma, individuals with Turner syndrome with detectable Y chromosome material (Mosaic Turner syndrome) should have their gonads prophylactically removed. In a population-based study, the cumulative risk for women with Turner syndrome and Y chromosome material was 7.9 percent by age 25 years.