SAT422 Gender Affirming Hormone Therapy in a Non-Binary Individual with Swyer Syndrome

Disclosure: J.M. Yohannan: None. T. Reisman: None. Background: Swyer syndrome is a rare genetic disorder of sexual development. Patients with Swyer syndrome require physiologic hormone replacement congruent with their gender identity in order to prevent bone loss. It is also important to screen for complications of this condition including osteopenia and dysgerminomas. Clinical Case: A 25 year old individual with a history of Swyer syndrome (46 XY gonadal dysgenesis) presents to clinic to discuss initiation of gender affirming hormone therapy. The patient identifies as non-binary and is interested in starting testosterone for masculinization. The patient was initially diagnosed with Swyer syndrome at age 23 during an evaluation for primary amenorrhea. At that time the patient had a laparoscopic gonadectomy and was found to have a dysgerminoma. Upon diagnosis the patient was started on hormone replacement therapy with norethindrone acetate-ethinyl estradiol 1 - 0.01 mg for bone loss prevention. They had a bone mineral density scan two years prior to presentation that was reportedly normal. To avoid the deleterious effects of hypogonadism they were started on estradiol-norethindrone 0.05 - 0.25 mg patch to provide bone protection. They were also provided testosterone gel for masculinization as part of their gender affirming care. Swyer syndrome is a disorder of sex development in which individuals with XY chromosomes develop phenotypically female Mullerian structures (uterus, fallopian tubes, and vaginal canal). Individuals with Swyer syndrome typically have non-functional “streak gonads” and are diagnosed during evaluation for primary amenorrhea. While some cases may be from a novel mutation, there are case reports showing that the condition can have an autosomal dominant, autosomal recessive, or even X-linked pattern of inheritance depending on the mutated gene. Patients with Swyer syndrome require physiologic doses of hormone replacement for maturation of secondary sex characteristics and bone health. For this patient in particular it is also important to provide appropriate hormone replacement congruent with their gender identity. Additionally, approximately 30% of patients with this condition may develop a gonadal tumor, including dysgerminomas. Because of this, patients frequently have their gonads removed upon diagnosis. Conclusion: Patient’s with Swyer syndrome should be on appropriate hormone replacement as they do not make endogenous sex steroids. Additional consideration of masculinizing hormone replacement should be made for patients that have a gender identity other than cisgender female. It is also important to screen patients for gonadal tumors as there is an increased incidence in this population. References: King, Thomas F.J.; Conway, Gerard S. Swyer syndrome. Current Opinion in Endocrinology & Diabetes and Obesity: December 2014 - Volume 21 - Issue 6 - p 504-510, doi: 10.1097/MED.0000000000000113 Presentation Date: Saturday, June 17, 2023