Primary bilateral macronodular adrenal hyperplasia (PBMAH), the most common cause of Cushing's syndrome due to bilateral nodules, is a heterogeneous disease at the clinical, hormonal and morphological levels. ARMC5 inactivating pathogenic variants are causative of PBMAH and rare variants of PDE11A have been associated with PBMAH. Leukocyte DNA of 354 PBMAH index cases was sequenced for ARMC5 and PDE11A genes by Next generation sequencing (NGS). Phenotypic characteristics of 334 of these patients were analysed to study the genotype/phenotype correlations. Seven out of 16 PDE11A variants were considered damaging according to in silico predictions: six missense variants (p.Tyr727Cys, p.Met623Arg, p.Tyr658Cys, p.Ag867Trp, p.Asn298Ser, p.Glu840Lys) and one stop-gain variant (p.Arg307Ter). In the cohort, 11.4% of patients had one of these variants and 19.2% had ARMC5 pathogenic variants. There was no significant difference in the distribution of PDE11A damaging variants according to ARMC5 status (p=0.83; OR=0.79, 95%CI [0.26-2.03]), neither in the distribution of ARMC5 pathogenic variants according to PDE11A status (p=0.83; OR=0.81, 95%CI [0.27-2.04]). Patients with PDE11A damaging variants had lower urinary free cortisol (UFC) (0.7 vs 1.25ULN, p=0.0002), midnight plasma cortisol (157.81 vs 222.19nmol/L, p=0.016) and number of adrenal nodules (3.46 vs 4.74, p=0.048) compared to PDE11A wild-type patients. Patients with ARMC5 pathogenic variants had a more severe phenotype with more frequent comorbidities and were more often treated by adrenalectomy (60%). PDE11A appears to be a modulator of PBMAH phenotype, damaging variants being associated with an attenuated form. This may contribute to the heterogeneity of PBMAH and could impact patients' management.
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