Thoracic aortic dissection in a young patient with an MYH9-related disorder: a case report

Pathogenic variants in the MYH9 gene cause MYH9-related disorders (MYH9-RD), typically characterized by congenital macrothrombocytopenia and aggregates of mutant non-muscle myosin heavy chain IIA in neutrophils (Döhle-like bodies) and other cells. Over time, individuals may develop sensorineural hearing loss, glomerular kidney disease, early-onset cataracts, and/or elevated liver enzymes. We report a young male patient presenting with bilateral congenital anterior polar cataracts, profound bilateral sensorineural hearing loss, vascular hepatoportal sclerosis, hypertension, and a history of alveolar hemorrhage of the lingula. At age 21, he was diagnosed with a thoracic aortic aneurysm, which progressed to acute dissection at 28. Genetic testing identified a de novo heterozygous in-frame deletion (c.1471_1473del; p.Glu491del) in MYH9, classified as likely pathogenic. No other pathogenic variants linked to thoracic aortic aneurysms or dissections were detected. This case is only the second reported thoracic aortic dissection in a patient with MYH9-RD. Given the expression and functional role of MYH9 in aortic tissue, this suggests the possibility of an association between MYH9-RD and aortic pathology. However, the limited number of reported cases precludes any inference of causality and warrants further functional and epidemiological investigation. Concurrent awareness of cardiovascular risk factors and individualized cardiovascular assessment may be considered, particularly in patients with hypertension or other clinical indications.