Smooth muscle dysfunction syndrome (SMDS) due to heterozygous ACTA2 arginine 179 alterations is characterized by patent ductus arteriosus, vasculopathy (aneurysm and occlusive lesions), pulmonary arterial hypertension, and other complications in smooth muscle-dependent organs.
In the present study, we further searched for mutations in human α-cardiac actin (ACTC1) and smooth muscle α-actin (ACTA2) genes as a possible cause of atrial septum defect type II (ASDII) and PDA.
We report a 7-year-old girl with an ACTA2R179H mutation manifesting with neonatal seizures due to multifocal infarcts, asymmetric motor deficits, global developmental delay, spasticity, congenital bilateral mydriasis, and a large patent ductus arteriosus.
A de novo mutation of the ACTA2 gene encoding the smooth muscle cell α-actin has been established in patients with multisystemic smooth muscle dysfunction syndrome associated with patent ductus arteriosus and mydriasis present at birth.