A Novel PRKAR1A Mutation Identified in a Patient with Isolated Primary Pigmented Nodular Adrenocortical Disease

• Main Authors: Sira Korpaisarn, Objoon Trachoo, Bhakbhoom Panthan, Rangsima Aroonroch, Ronnarat Suvikapakornkul, Chutintorn Sriphrapradang
• Format: Article
• Language: English
• Published: Karger Publishers 2017-08-01
• Series: Case Reports in Oncology
• Subjects: Adrenal adenoma; Cushing syndrome; Mutation; Penetrance; Splice site
• Online Access: http://www.karger.com/Article/FullText/479585

Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of Cushing syndrome, especially the isolated form without Carney complex, associated with germline mutations in PRKAR1A, the protein kinase A regulatory subunit type 1 alpha gene. We report a 31-year-old female who presented with secondary amenorrhea, cushingoid appearance, and hypertension without Carney complex. Biochemical laboratory examinations confirmed the ACTH-independent adrenal Cushing syndrome with negative Liddle test. A small right adrenal adenoma of 0.8 cm was shown on computed tomography while magnetic resonance imaging revealed nodularity of both adrenal glands. The histological report confirmed PPNAD using laparoscopic right adrenalectomy, and subsequent left adrenalectomy was performed 6 months later. She had inherited heterozygosity of a novel germline mutation of the PRKAR1A gene (g.114213T>G or c.709-5T>G). This splice site mutation results in exon 8 skipping. Her father carrying the same mutation had no clinical features of either PPNAD or Carney complex. This novel PRKAR1A gene mutation, c.709-5T>G, is reported here for the first time manifesting as an incomplete clinical expression of the isolated form of PPNAD and being inherited with low penetrance unlike other inherited mutations of the Carney complex which have a penetrance of almost 100%.