Prevalence and characteristics of gonadoblastoma in a retrospective multi-centre study with follow-up investigations of 70 patients with Turner syndrome and a 45,X/46,XY karyotype
Abstract
Introduction: A gonadectomy is currently recommended in patients with Turner syndrome (TS) and a 45,X/46,XY karyotype, due to a potential risk of gonadoblastoma (GB). However, the quality of evidence behind this recommendation is low. Objective: Evaluate the prevalence of GB, its characteristics, as well as its risk factors, according to the type of Y chromosomal material in the karyotype. Methods: Our study within French rare disease centers included patients with TS and a 45,X/46,XY karyotype, without ambiguity of external genitalia. Clinical characteristics of the patients, their age at gonadectomy and gonadal histology were recorded. The regions of the Y chromosome, the presence of TSPY regions and the percentage of 45,X/46,XY mosaicism were evaluated. Results: Seventy patients were recruited, with a median age of 29.5 years [21.0-36.0] at the end of follow-up. Fifty-eight patients had a gonadectomy, at a mean age of 15 ± 8 years. A GB was present in 9 cases. Two were malignant, discovered at the age of 14 and 32 years, without metastases. Neither the percentage of XY cells within the 45,X/46,XY mosaicism, nor the number of TSPY copies, were statistically different in patients with or without a GB (p=0.37). However, the entire Y chromosome was frequent in patients with GB (6/9). Conclusions: In our study, including a large number of patients with 45,X/46,XY TS, the prevalence of gonadoblastoma is 12.8 %. An entire Y chromosome appears as the main risk factor of GB, and should favor early gonadectomy.