Type A Aortic Dissection, Apparent Mineralocorticoid Excess Syndrome, and Syndromic Aortic Root Dilatation

Objective: To determine the cause of acute life-threatening aortic root dissection in a 36-year-old male with a long-standing history of apparent mineralocorticoid excess (AME) and hypertension since childhood. Methods: Cortisol metabolites were analyzed by urine tandem mass spectrometry. Screening for DNA variants was performed using the Marfan Syndrome and Related Aortopathies NextGen Sequencing Panel (Collagen Diagnostic Laboratory, University of Washington, Seattle). Cytogenetic microarray analysis (CombiMatrix, CA) was performed. Sequencing of the 11β-hydroxysteroid dehydrogenase type 2 gene (HSD11B2) in a region of homozygosity (ROH) identified on microarray analysis was targeted using Sanger sequencing (Prevention Genetics) on an ABI 3730x1 capillary sequencer. Results: There was reduced urinary excretion of all 11-carboxyl containing steroids and high excretion of free cortisol and its metabolites, consistent with a diagnosis of AME. Microarray analysis revealed 4 ROHs. One ROH contained the HSD11B2 gene. The patient was found to be homozygous for a sequence variant designated as c.622CC>T (p. Arg208Cys) in the HSD11B2 gene, as previously reported in an unrelated patient, therefore confirming the pathogenicity of this mutation. No mutations were identified on the core vascular aneurysm panel. Conclusion: This is the first report of aortic aneurysm formation and dissection in a patient with confirmed AME. We hypothesize that the mineralocorticoid effect of high free cortisol and its metabolites is an independent causative factor for aortic aneurysm formation. Abbreviations: AME apparent mineralocorticoid excess; BP blood pressure; HSD11B2 11β-hydroxysteroid dehydrogenase type 2