Organ transplantations cause discrepancy in results from cell-free DNA (cfDNA) testing, but scientific literature is scarce. A 33-year old gravida underwent cfDNA testing, which showed high levels of Y chromosome (ChrY) in the maternal bloodstream. The ChrY pattern was comparable to an adult male reference. As a result, cfDNA testing was only informative for autosomes. Routine 20-week ultrasound scan showed no structural alterations and the presence of female external genitalia. Post-clinical research revealed that the patient received a bone marrow transplant from a male donor several years before. Fluorescence in situ hybridization showed that 100% of nuclei analysed from the patient’s lymphocytes presented a ChrY. This case demonstrates ChrY can be used as a marker to avoid sex discrepancies in certain patients with organ transplants.

中文翻译：

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Y染色体作为器官移植患者性别差异的标志物：一例报告

器官移植导致无细胞DNA（cfDNA）测试结果的差异，但科学文献稀缺。一名33岁的孕妇进行了cfDNA测试，结果显示孕妇血流中的Y染色体（ChrY）水平较高。ChrY模式可与成年男性参考相比。结果，cfDNA测试仅对常染色体有用。常规的20周超声扫描未发现结构改变，也没有女性外生殖器的存在。临床后研究表明，该患者几年前接受了男性捐赠者的骨髓移植。荧光原位杂交表明，从患者淋巴细胞分析的细胞核中有100％呈现ChrY。这个案例表明，ChrY可以用作避免某些器官移植患者性别差异的标志物。