ESPE Abstracts

Background: The 45,X/46,XY mosaicism represents a wide spectrum of phenotypes, from phenotypically normal females to males and varying degrees of genital ambiguity. Growth seems to be impaired in these patients. It is associated with increased risk of germ cell tumours.

Aim: To evaluate growth, gonadal function and tumour risk in a large group of children with 45,X/46,XY mosaicism in a single tertiary centre.

Methods: We conducted a retrospective review of the records of patients with 45,X/46,XY mosaicism who presented from 1989 to 2020. The growth and histological results of gonadectomy or biopsy of patients were evaluated. Patients were divided into 3 groups as those with female external genitalia, ambiguous genitalia, or male external genitalia with respect to phenotypic characteristics at diagnosis.

Results: 45 patients were included. The age at diagnosis ranged from 0.03 to 17.5 years. Twenty-eight patients exhibited ambiguous genitalia, 14 patients had female external genitalia and 3 patients had normal male external genitalia. Twenty-four patients were raised as females and 21 patients as males. HeightSDS of 14(31.1%) patients were below -2 SDS at diagnosis and median heightsSDS of 21 patients diagnosed before 2 years of age was -0.99(-2.22/0.12); however median heightSDS in 24 patients diagnosed after 2 years of age was -2.61(0.3/-6.2). Short stature was more frequent in females than in males (50% vs 9.5%). Twenty-one patients reached adult height (AH). Growth hormone (GH) treatment was initiated in10 patients. Although AHSDS of GH treated patients was significantly greater than their heightSDS before GH therapy (P = 0.013), it was not significantly different from AHSDS of the untreated group. Seventeen (37.8%) patients exhibited phenotypical features and congenital anomalies of Turner syndrome other than short stature. In female external genitalia group, majority of patients (78.6%) had bilateral streak gonads, in ambigious genitalia group 37.5% of patients had bilateral dysgenetic testes, 50% of patients had unilateral dysgenetic testis and contralateral streak gonads. In ambigious group, 2 patients, raised as female, had gonadoblastoma and germ cell neoplasia in situ in their bilateral abdominal dysgenetic testis. In female external genitalia group, one patient with bilateral streak gonad had gonadoblastoma.

Conclusions: Patients with 45,X/46,XY should be screened for congenital anomalies like Turner syndrome. GH therapy seems to improve AH of patients. Both ambiguous group and female group have increased risk of germ cell tumors.