FRI188 Exploratory Genomic Analysis From A Brazilian PMAH-Family With ARMC5 Alteration With Insidious Pattern Progression Of The Disease

Disclosure: H.L. Charchar: None. A.W. Kuhn: None. B.M. Mariani: None. M.Y. Nishi: None. F.L. Ledesma: None. M.C. Zerbini: None. F.Y. Tanno: None. V. Srougi: None. J.L. Chambo: None. M.Q. Almeida: None. B.B. Mendonca: None. M.C. Fragoso: None. Background: The clinical evolution of primary macronodular adrenal hyperplasia (PMAH) is usually slow over many years and is related to the insidious progression of hypercortisolism. The disease presents an autosomal dominant inheritance pattern with incomplete penetrance. Germline heterozygous mutations in the ARMC5 are present in 10% to 55% of the patients. The long-term follow-up of patients harboring germline ARMC5 pathogenic variants with normal evaluation will provide us with important insights regarding the outcomes. Clinical case: A 53-year-old man (index-case) was referred by the cardiologist to our service in October 2012, due to resistant hypertension (HTA), type 2 diabetes mellitus, dyslipidemia, and BMI of 32.4 kg/m(2). Hormonal data: low ACTH (<5 pg/mL) and no suppression of cortisol after the overnight DST-1mg (22.7 µg/dL); late-night salivary cortisol, urinary free cortisol, aldosterone/renin ratio and plasma metanephrines were in the normal range. A CT scan showed bilateral enlargement of the adrenals associated with multiple macronodules. He underwent an adrenal-sparing surgery (total adrenalectomy of the left adrenal and partial adrenalectomy of the right adrenal). The macroscopic and histological appearance was consistent with PMAH. Leucocyte DNA genotyping identified the germline heterozygous ARMC5 pathogenic variant in exon 1 c.280del, p.(Ser94Argfs*43). This variant was identified in 3 of the 10 relatives investigated (son#1, daughter#2 and grandson#3). In 2021, the 37-year-old son#1 presented with a BMI of 32.6 kg/m(2). Autonomous cortisol secretion was confirmed (cortisol after DST-1mg = 6.7 µg/dL). CT scan showed bilateral enlargement of the adrenals, similar to his father (index-case), with a larger left adrenal. Unilateral left adrenalectomy was performed, and PMAH was histologically confirmed. In 2018, the 21-year-old daugher#2 had normal adrenal function. More recently, in December 2022, she presented with an important weight gain (44kg in 4 years), without any specific signs and symptoms of hypercortisolism. Hormonal investigation showed a possible autonomous cortisol secretion (cortisol after DST-1mg = 2.2 µg/dL); the CT scan demonstrated an adrenal diffusely thickened with several nodules, especially on the left side, as the other relatives. Up to now, she has been using ketoconazole. All of them did not present meningioma of CNS. The grandson#3 with 11-year-old, is asymptomatic so far. Clinical Lesson: PMAH is a heterogenous and underdiagnosed disorder and is more genetically associated than previously thought. Therefore, a careful hormonal-genetic-clinical-radiological study of the relatives of index cases permits the diagnosis of many unsuspected familial-cases, including asymptomatic patients. Surgical or medical treatment should be considered for these patients to avoid progression to a possible overt Cushing syndrome. Presentation: Friday, June 16, 2023