FRI556 Thyroid Autoimmunity Leading To Premature Ovarian Insufficiency (POI) In A Euthyroid Young Woman

Disclosure: P. rimal: None. M. Moeed: None. C. Musurakis: None. A. Ojha: None. W. Akhtar: None. C.P. Barsano: None. M.F. Siddiqui: None. Introduction: Premature Ovarian Insufficiency is rare in young women and affects only 0.1% before the age of 30. The causes of POI in most cases remain unidentified, with autoimmunity being responsible for 4-30% of the cases. We present the case of a young euthyroid woman who presented for the evaluation of primary amenorrhea and diagnosed with POI associated with thyroid autoimmunity. Clinical Case: A 28-year-old Afghani woman with no known co-morbidities was referred to endocrinology clinic for the work up of primary amenorrhea. She was a goitrous and had normal secondary sexual characteristics and a history of withdrawal bleeding with OCP. There was no known personal or family history of autoimmune disease. Work up revealed hypergonadotropic hypogonadism with high FSH, 55 mIU/ml[Ref range for postmenopausal woman 16.7-113], high LH, 20.28 mIU/ml [Ref range for postmenopausal woman 10.8-58.69] and low estradiol, <2 pg/ml. Anti-Mullerian hormone was low, <0.08ng/ml [RefRange 0.69-13.39] signifying inadequate ovarian reserves and pelvic ultrasound confirmed atrophic ovaries. Etiological work up revealed normal female karyotype, 46XX, and negative FMR gene mutation testing for Fragile X syndrome. Thyroid functions were normal TSH, 3.3 mIU/L (0.27-4.2) and Free T4, 1.29 ng/dl[Ref Range 0.70-2.7]. Autoimmune work up was negative for adrenal 21-OH antibody and anti-ovarian antibodies. However, patient had strongly positive thyroid peroxidase (TPO) antibodies, 613.77 mIU/L[Ref range 0.0-9.0] consistent with thyroid autoimmunity. DXA scan revealed osteopenia. Thus, the diagnosis of POI associated with thyroid autoimmunity was established. HRT with estradiol patch and progesterone was initiated. Calcium, Vitamin D supplements and fertility counseling were provided. Conclusion: Thyroid disease is the most common autoimmune disease associated with POI. Studies have shown higher risk of POI and infertility in patients with Hashimoto’s and Graves’ diseases with co-existing high titers of TPO or anti-thyroglobulin antibodies. Ovaries are subject to autoimmune attack that leads to diminished ovarian reserves. However, until now the association of isolated elevation of TPO antibodies with POI has not been established. A Study by Osuka et al. did not find any significant difference in AMH levels between TPO and non-TPO positive euthyroid women and concluded that unlike hypothyroid women, thyroid autoantibodies were not likely to influence ovarian reserves in euthyroid women. Our case is unique where POI is associated with isolated elevation of TPO antibodies in the absence of clinical thyroid disease. This signifies the possibility that ovarian failure may precede the onset of thyroid disease in patients with thyroid autoimmunity and should be suspected and treated at an early stage, before ovarian reserves are diminished. Presentation: Friday, June 16, 2023