O-139 Testicular mosaicism in non-mosaic Klinefelter Syndrome patients with focal spermatogenesis

Abstract Study question Do testis-specific cells have a normal karyotype in regions with spermatogonia (SPG) and ongoing spermatogenesis non-mosaic Klinefelter Syndrome (KS) patients? Summary answer While SPG Sertoli (SC) 46,XY spermatogenesis, most Leydig (LC) peritubular myoid (PTMC) 47,XXY karyotype. What is known already Although the majority of KS patients azoospermic, some focal (FS) can children artificial reproductive technologies. However, genetic origin FS unknown. Independent FS, dimorphism sex chromatin has been reported amongst seminiferous tubules men. other not clearly revealed so far. The histone-3-lysine-27-tri-methylation (H3K27me3) modification involved suppression extra X chromosome, its immunohistochemical staining allows analysis chromosome aneuploidy. design, size, duration Testicular biopsies were taken from 7 whom spermatozoa found by testicular sperm extraction (TESE). Muscle female colon samples used as positive control. Participants/materials, setting, methods After tissue processing paraffine embedding, sections cut at 5 µm. Immunohistochemical was performed antibodies for H3K27me3 (inactive chromosome), MAGE-A4 (SPG), SOX9 CYP17A1 (LC). PMTC evaluated according to their position around elongated shape. Inactive (Xi) (Xi+) Xi negative (Xi-) counted and, Xi+ having karyotype; Xi- Main results role chance A total 25 SPG+ tubule detected 4 samples. Both SC Xi-, i.e. karyotype, all these tubules. In cell only (SCO) tubules, SCs (i.e. 47,XXY), while others they 46,XY). rate SCO containing 31.6%. Similarly, ratio muscle control 31.0%. PTMCs surrounding present, or 47,XXY). LCs 47,XXY) percentage (21.4%) LC (24.6%) low compared (31.0%), suggesting mosaicism well. Limitations, reasons caution fact that nuclei coincide section plane are mitotic stage limit detection H3K27me3. To overcome this limitation, could be different techniques on intact isolated fresh tissue. Wider implications findings occurs SPGs SCs. Non-mosaic (diagnosed blood cells) may present mosaicism, increasing chances retrieval. Trial registration number Not applicable