[Macronodular adrenal hyperplasia causing Cushing's syndrome due to ARMC5 gene mutation.].

Our 69-year-old female patient was investigated for a 20 kg weight gain over 2 years. The patient's medical history included hypertension, hyperuricemia, bilateral cataract surgery and musculosceletal complaints. Diabetes mellitus was not found. Physical examination revealed abdominal obesity, proximal myopathy and atrophic, vulnerable skin. The "overnight", low-dose and long, low-dose dexamethasone suppression tests indicated autonomous cortisol overproduction (plasma cortisol level: 172.6 and 153.2 nmol/L, cut-off: 50 nmol/L). The suppressed ACTH (<1.11 pmol/L, normal value: 1.12-10.75 pmol/L) suggested ACTH-independent hypercortisolism. Abdominal CT described macronodular enlargement of both adrenals. The size of the largest nodule was 23 × 20 mm in the right, and 24 × 30 mm on the left side (with -33 ± 37 HU density values on native scans). The 131I-cholesterol adrenal scintigraphy and SPECT/CT showed almost equally intensive radiopharmacon uptake on both sides. Based on the clinical results, bilateral macronodular adrenal hyperplasia associated with ACTH-independent hypercortisolism was diagnosed. Genomic DNA was obtained from the peripheral blood leukocytes. Targeted sequencing of 25 genes potentially involved in adrenal tumorigenesis revealed a new disease-causing armadillo repeat-containing 5 (ARMC5) gene mutation (c.1724del28 bp, g.31,476,067-31,476,094). Because of the autosomal dominant inheritance of this genetic alteration, the patient's two children underwent genetic screening for the ARMC5 mutation. The same mutation was found in the younger child of our patient. To the best of our knowledge, this is the first published Hungarian case of ARMC5 mutation with bilateral macronodular adrenal hyperplasia and ACTH-independent Cushing's syndrome. The genetic alteration is present in two generations of the family of the index patient. Orv Hetil. 2023; 164(32): 1271-1277.