SAT-306 An Atypical Presentation of Klinefelter Syndrome

Introduction: Most Klinefelter syndrome (KS) males exhibit hypergonadotrophic hypogonadism and decreased sexual desire, but normal testosterone in the context of elevated gonadotropins should not exclude KS. Additionally, decreased sexual desire may not be seen in all KS males. Clinical Case: A 13-year-old adopted male, with ADHD, Tourette’s, and depression, was referred by his psychiatrist due to "preoccupation with sex" and early puberty (axillary and pubic hair since age 8-9). Mother reported finding adult magazines in his room, aggressive behavior, immaturity, and impulsivity. He required class support for algebra, english, and geography. His medications included amphetamine/dextroamphetamine, guanfacine, and escitalopram. On physical exam, his height was 68%, weight 24%, and BMI 5%. Tanner stage could not be assessed due to grooming, but he had 6-8 ml testes. Bone age was advanced at 17 years at age of 13 years and 8 months. Laboratory testing revealed LH 19 mIU/ml, FSH 38 mIU/ml, testosterone 403 ng/dl (Tanner 5, 350-970). Brain MRI did not show any pituitary abnormalities. Further evaluation for his advanced bone age and early adrenarche showed normal androstenedione (48 ng/dL), DHEAS (121 ug/dL), and 17OHP (81 ng/dL). Testicular ultrasound showed 3 lobular 3 mm hypoechoic masses along the left mediastinum testes, suspicious for adrenal rests (ART); however urology did not feel the lesions were consistent with ART as they were unilateral. Due to concern for CAH, stimulation testing was done and was normal (baseline 17OH pregnenolone 18 ng/dl, 17OHP 102 ng/dl, 11-DOC <10 ng/dl; stimulated 17OH pregnenolone 896 ng/dl, 17OHP 256 ng/dl, 11-DOC 159 ng/dl), Repeat labs showed LH, 30 mIU/mL, FSH 52 mIU/mL, testosterone 646 ng/dL. Continued elevation in gonadotropins prompted chromosomal testing which revealed XXY, consistent with Klinefelter syndrome. Conclusions: Normal testosterone levels associated with elevated gonadotropins may be an early manifestation of testicular failure associated with KS and karyotype should be considered as part of the diagnostic evaluation. Additionally, hypersexual behavior can be seen in KS males and should not preclude evaluation for KS in males with hypergonadotrophic hypogonadism. References: Gravholt CH, Chang S, Wallentin M, Fedder J, Moore P, Skakkebæk A. Klinefelter Syndrome: Integrating Genetics, Neuropsychology, and Endocrinology. Endocr Rev. 2018 Aug 1;39(4):389-423.