A NEW-FOUND ARMC5 GERMLINE VARIANT IN PRIMARY BILATERAL MACRONODULAR ADRENAL HYPERPLASIA USING WHOLE-EXOME SEQUENCING AND PROTEIN PREDICTIVE ANALYSIS.

Objective: ARMC5 mutations are responsible for the development of primary bilateral macronodular adrenal hyperplasia (PBMAH). In this study, we aimed to report a novel ARMC5 germline variant in a PBMAH patient family.

Method: CT examination and dexamethasone suppression test (DST) were used in the diagnosis of PBMAH. Sanger sequencing was used to validate the familial heredity. For the novel variant, protein predictive analysis was performed to study the changes of secondary and tertiary structures and hydrophobicity.

Results: A 45 years old male (proband, III-1) was diagnosed as PBMAH. Whole-exome sequencing (WES) was performed, finding one mutation: c.719_ 724dup, p Arg240_ Pro241dup. Sanger sequencing showed the II-2, III-1, IV-1 with heterozygous gene, confirming the familial heredity. For protein predictive analysis, the predicted secondary structure of variants has one alpha-helix structure incomplete compared with normal ARMC5. The tertiary structure could draw the same conclusion, that hydrophobicity decreases after mutation.

Conclusion: We reported a new-found ARMC5 germline variant in PBMAH using WES and protein predictive analysis. With the help of WES, early diagnosis of PBMAH could help variant carriers to prevent the occurrence of cancer by lifetime follow-up.