MR Imaging Diagnosis of ACTA2

Smooth muscle alpha-2 actin (ACTA2) mutations are associated with diffuse smooth-muscle dysfunction syndrome and produce distinct imaging features. Clinical manifestations include intrathoracic large-vessel disease, nonreactive mydriasis, bladder hypotonia, and intestinal dysmotility. ACTA2 mutations are associated with childhood stroke due to diffuse cerebral arteriopathy distinct from moyamoya disease. Recognition of this syndrome has important clinical and prognostic implications. The purpose of this article is to review the unique imaging phenotypes associated with ACTA2 mutations, including vascular and nonvascular abnormalities.