日本小児循環器学会雑誌 Pediatric Cardiology and Cardiac Surgery

Noonan syndrome (NS) is an autosomal dominant disorder characterized by facial dysmorphism, short stature, and congenital heart defects. NS is caused by dysregulation of the RAS-MAPK pathway, and multiple gene mutations of this pathway have been identified. Common cardiovascular disorders in NS include pulmonary valve stenosis, atrial septal defect, and hypertrophic cardiomyopathy. Coronary artery abnormalities have also been reported as rare vascular complications. We present the case of a male patient with NS with the SHOC2 mutation. The patient developed progressive dilation of the left coronary artery as well as a ventricular septal defect (VSD) and right ventricular outflow tract stenosis. VSD patch closure was performed at the age of 4 due to progressive aortic regurgitation from prolapse of the non-coronary aortic cusp. Coronary artery dilation was first detected at the age of 11. Gene analysis conducted at the age of 16 identified the SHOC2 mutation. Although 14 cases of NS with coronary artery dilation have been previously reported, this is the first report of NS with the SHOC2 mutation complicated by such a rare coronary arterial abnormality. The clinical characteristics and genetic backgrounds of those cases as well as the mechanism of coronary dilation are discussed.