Whole-genome sequencing revealed armadillo repeat containing 5 (ARMC5) mutation in a Chinese family with ACTH-independent macronodular adrenal hyperplasia

Abstract

Primary macronodular adrenal hyperplasia (PMAH), also known in the past as bilateral macronodular adrenalhyperplasia or adrenocorticotropin (ACTH)-independent macronodular adrenal hyperplasia, is a rare type of Cushing’s syndrome (CS) and is associated with bilateralenlargement of the adrenal glands. It accounts for <1% of all endogenous cases of CS. In order toidentify the pathogenic mutations in the causative gene of (AIMAH pedigrees, Whole-genome sequencing of three patients in family I was used to retrieve candidate causative genes. Meanwhile, the causative gene was identified by Sanger sequencing from the two pedigrees. Sequencing of ARMC5 exons of three patients was carried out to identify somatic mutations. Moreover, haploid clone of one tumor DNA sample was conducted. ARMC5 was the causative gene of two pedigrees confirmed by whole-genome sequencing (WGA) and Sanger sequencing. The variant sites of the two families were c.C943T (p.R315W) and c.C1960T (p.R654X), respectively. Autosomal dominant inheritance of AIMAH was confirmed by genotypes of one family member. Several somatic mutations were discovered in tumor DNA samples. In addition, haploid clone of tumor DNA was confirmed by germline mutation and somaticmutation, which suggested the pathogenic mechanism of “two-hit-model.” ARMC5 was the causative gene of AIMAH pedigrees. This AIMAH in this study presented autosomal dominant inheritance, fitting to Mendelian inheritance law. However, the pathogenic mode of this disease showed as compound heterozygote.