Detection of hidden Y mosaicism in Turner's syndrome: Importance in the prevention of gonadoblastoma

Abstract

The presence of Y chromosome fragments in patients with Turner's syndrome (TS) is known to increase the risk of gonadoblastoma. The investigation of Y sequences is usually performed only in the presence of marker chromosomes and therefore does not rule out the presence of hidden mosaicism in patients with 45,X TS without any marker.Aims: 1. To investigate the presence of hidden Y mosaicism in non-mosaic 45,X patients with TS, using samples from different tissues, and its association with the development of gonadoblastoma.Study design: Twenty patients with a 45,X karyotype were studied. The SRY and DYZ3 sequences were amplified by PCR, using genomic DNA from peripheral blood, oral epithelial,cells and hair roots. Prophylactic gonadectomy was offered to the Y-positive patients.Results: The analysis of the different tissues revealed that seven (35%) out of the 20 patients studied presented hidden chromosome Y mosaicism. Four of these patients underwent prophylactic gonadectomy, and bilateral gonadoblastoma was found in one of them.Conclusions: A systematic search for hidden Y chromosome mosaicism in patients with TS and 45,X karyotype is justified by the possibility of developing gonadoblastoma.