Congenital Fibrosis of Extraocular Muscles Type 1 with Progression of Ophthalmoplegia

Abstract

Background Congenital fibrosis of the extraocular muscles type 1 (CFEOM1) is a congenital, non-progressive autosomal-dominant disorder with bilateral oculomotor nerve palsy due to mutations in the kinesin motor protein gene KIF21A. - Results We present a 60-year old patient with CFEOM1 due to the common C2860T mutation in KIF21A. At the age of 37, he complained about newly occurred diplopia, which implies the capability of binocular vision before. The divergence of both globes progressed and the poor residual movement on attempted adduction and upgaze completely disappeared during the sixths decade. Clinical and electromyographic examination showed isolated involvement of the oculomotor nerve. - Conclusion Apparently, progression of impaired ocular motility is not contradictory to the diagnosis of this congenital developmental disorder. Mechanical, contracture-like mechanisms as known from other types of strabism or persistent overuse of the reduced number of oculomotor a-motoneurons are generally considered as a reason for clinical progression. However, regarding the underlying known molecular basis of CFEOM1, a continuous disease progression due to the kinesin dysfunction cannot be excluded.