Demystifying the gender of patient after allogeneic bone marrow transplantation from an opposite-sex donor: A case report

RATIONALE: Bone marrow transplantation (BMT) is an established therapy for hematological malignancies. In recent years, with the advancement of medical research, evaluating the efficacy of BMT in recipients by detecting the presence or absence of chromosomes from an opposite-sex donor has been widely recognized. Numerous cases have shown that the sex hormone levels of recipients who receive BMT from the opposite sex will change significantly. However, whether such hormonal changes will impair sexual function or lead to physiological sex-related manifestations, or even cause changes in the biological sex of BMT recipients, these questions make people cannot help but think deeply. Herein, we report a case of a male patient who received allogeneic BMT from a female donor, demonstrating that transplantation only replaced the recipient's hematopoietic stem cells and did not change the patient's biological sex. PATIENT CONCERNS: We report a 22-year-old male who was diagnosed with azoospermia during a recent physical examination and sought medical attention at our hospital. DIAGNOSES: Semen examination showed no sperm, and the analysis of the peripheral blood chromosome karyotype is 46,XX. The preliminary clinical diagnosis is azoospermia with sexual dysfunction. INTERVENTIONS: The results of Y-chromosome microdeletion in peripheral blood could not be interpreted. After reviewing the patient's history, we only found that he had received a BMT from an opposite-sex donor for chronic myelocytic leukemia 14 years ago, when he was only 8 years old. The peripheral blood and buccal mucosal swabs were collected for Y-chromosome microdeletion examination again. At this point, the truth has finally come to light: At this point, the etiology became clear: The patient's peripheral blood showed chimeric DNA from both the BMT donor and recipient, while the buccal mucosal swabs-originating from embryonic development-accurately reflected his pretransplantation genetic profile. OUTCOMES: The patient, being only 22 years old and having no intention of getting pregnant at present, received no further medical treatment. LESSONS: This case report demonstrates that while sex-mismatched BMT may alter secondary sexual characteristics, it does not fundamentally change the recipient's genetic sex or core gender identity.