Unravelling complex mosaicism of sex chromosomes in a patient with primary amenorrhea through cytogenetic analysis on urothelial cells.

Abstract Objective Sex chromosome mosaicism remains challenging in the study of disorders of sex development (DSD). Aneuploid cells in the developing gonad play a major role in sex determination. Therefore, it is necessary acknowledge their presence by different methods. Our aim was to stand out the utility of urothelial cells for unravelling complex and hidden cell lines in DSD patients. Case report Herein we report on a 19-year-old female with primary amenorrhea, short stature without ambiguous external genitalia. She had a 45,X/46, XY karyotype in leukocytes. Interphase FISH revealed hidden 45,X/47,XYY/47,XXY/46,XY/46, XX mosaicism in leukocytes and urothelial cells. Conclusion These findings highlight the importance of investigating sex chromosome mosaicism in other tissues. Of particular interest in cases of DSD are the cells from the urinary epithelium, which may reflect the cell composition of the urogenital ridge, the analysis of these cells should be considered within the clinical assessment of DSD patients.