To determine whether congenital fibrosis of the extraocular muscles (CFEOM) with Marcus Gunn jaw-winking phenomenon (MG) can result from mutations in the KIF21A gene encoding a kinesin motor protein.
To demonstrate the clinical characteristics and determine mutations in the KIF21A gene, encoding a kinesin motor protein in patients with congenital fibrosis of the extraocular muscles (CFEOM) type 1.
To describe the phenotypic characteristics and clinical course of a sporadic case of congenital fibrosis of the extraocular muscles (CFEOM) and Möbius syndrome with a de novo mutation in the KIF21A gene encoding a kinesin motor protein.