SAT-028 POU1F1 Mutation With Manifestation of Pan-hypopituitarism In Adulthood: Case Report

Abstract Disclosure: N.B. Dal-Prá: None. M.L. Quinhone: None. Introduction: Panhypopituitarism is a clinical condition characterized by the absence or reduction of secretions of two or more pituitary hormones. It might be caused by tumors or iatrogenic causes and in rare cases, due to a congenital origin related to transcription factors mutations. The POU1F1 mutation is rare compared to other mutations, with dominant or recessive forms and only 1,6% of cases appear spontaneously. It normally manifests itself mainly by a deficiency in GH, PRL and TSH production. The POU1F1 mutation phenotype is variable especially in relation to the beginning of clinical manifestation. There are several POU1F1 gene mutations reported in literature, with the diagnosis age varying from 6 months to 18 years old, with rare manifestations in adulthood. The objective of this is report the case of a patient who developed symptoms related to POU1F1 mutation at the age of 25, presenting with secondary amenorrhea and central hypothyroidism, without issues related to GH and PRL production. CASE REPORT Female patient, 25 years old, attends endocrinological appointment with sudden onset amenorrhea for 6 months with no other associated symptoms. She is nulliparous, had been perfectly healthy and had adequately developed her sexual characters (Tanner Stage-5), menarche at 13 years old and regular menstrual cycles. Initially, structural abnormalities and possible chronic anovulation were discarded. Exams requested in November 2021: TSH 0.6 (0.38-5.3); T4L 0.6 (0.61-1.1); estradiol <15 (20-622); FSH 8.6 (1.79-22.5); IGF-1 167 (89-305); LH 7,57 (2.1-103); 17-OHP 0.76 (0.20-4,5); PRL 8.3 (2.8-29.2). No abnormalities observed in the sella turcica MRI. New tests requested in April 2022: TSH 0.61 and T4 0.65, with levels very close to the lower limit of normality, confirming the possibility of central hypothyroidism. The replacement of Levothyroxine 50mcg was started. Reevaluated in July 2022, presenting amenorrhea for more than 1 year, with lower levels of TSH (0.41), T4 (0.78), FSH (5.0) and LH (10.0), confirming the diagnosis of panhypopituitarism. All iatrogenic and structural causes were ruled out, it was requested a genetic test, with positive result for a heterozygous and recessive POU1F1 mutation. Conclusion: There is a wide spectrum of clinical and laboratorial manifestations among patients with hypopituitarism. For that reason, it is essential to have a careful analysis of the clinical phenotype and associated morphological findings in investigating cases of congenital hypopituitarism. So far, a lot of cases have not yet received their molecular identity, and several mutations and epigenetic interactions will have to be thoroughly studied in order to explain unclear cases of congenital hypopituitarism. Presentation: Saturday, July 12, 2025