Familial moyamoya disease in two Turkish siblings with same polymorphism in RNF213 gene but different clinical...

Moyamoya disease is an uncommon, progressive, and occlusive cerebrovascular disorder, predominantly affecting the terminal segment of the internal carotid arteries and its main branches. This occlusion results at the formation of a compensatory collateral arterial network (moyamoya vessels) developing at the base of the brain. The c.14576G>A variant in ring finger protein 213 (RNF213) was recently reported as a susceptibility gene for moyamoya disease.

We describe two Turkish pediatric siblings with moyamoya disease born to consanguineous, unaffected Turkish parents.

The first patient (proband) is a 2-year-old boy who presented with afebrile focal seizures, moderate psychomotor retardation, paresis in the left upper and lower extremity, multiple infarctions of the brain, stenosis of the bilateral internal carotid artery and the middle cerebral artery, and stenosis of the right posterior cerebral artery. The second patient is a 10-year-old girl who is an elder sister of proband. She showed normal psychomotor development, millimetric signal enhancement without diffusion limitation of the brain, and stenosis of the bilateral internal carotid artery.

We herein report pediatric sibling patients of moyamoya disease who have homozygous wild-type c.14576G>A variant in RNF213, showing different clinical course and disease severity. This is the first report of pediatric siblings with moyamoya disease from Turkey validating the genetic background of most frequent variant in East Asian patients with moyamoya disease.