P-055 MONOZYGOTIC TRANSGENDER MALE TWINS: A CASE REPORT HIGHLIGHTING GENETIC CONCORDANCE IN GENDER DYSPHORIA

Abstract Introduction Gender dysphoria is defined as a marked and persistent incongruence between an individual’s assigned gender at birth and their experienced or expressed gender identity. After psychiatric evaluation and follow-up, patients are referred to the Endocrinology clinic for hormonal management. Here, we present monozygotic transgender male twins followed up in our clinic. Clinical Case Monozygotic twins, 27-year-old individuals assigned female at birth, were referred to our endocrinology clinic by the psychiatry department in July 2024. They live with their mother in a central of Istanbul. Their parents divorced when they 6, and they have had no contact with their father since. Both completed developmental milestones (walking, speech) at expected ages. Twin 1 graduated with a degree in business administration, while Twin 2 completed high school. In childhood, both reported enjoying dressing like boys and playing with boys. They stated that they did not feel the need to discuss their gender identity with each other, because they both accepted themselves and each other as being in male bodies. Twin 1 recalled having a crush on a girl in the first grade. At their initial endocrinology visit, both patients reported regular menstrual cycles, with no significant hirsutism, alopecia, or androgenic symptoms. Neither had a history of chronic illness or regular medication use, but both smoked approximately half a pack of cigarettes daily. Both had 46,XX karyotypes. On physical examination; both twins had a history of mastectomy and their Ferriman–Gallwey score were: 6/7 Laboratory results showed (Twin 1/Twin 2): Prolactin: 10.1/21 ng/mL (4–20) 17-OH-Progesterone: 0.46/0.91 ng/mL (