[Familial congenital horizontal gaze paralysis].

Familial congenital horizontal gaze paralysis is a rare disorder supposedly transmitted in an autosomal recessive fashion. Typically, all horizontal, conjugate eye movements are absent. Most patients are orthotropic with regular binocular function. The complete lack of horizontal eye movements is compensated for by turning the head in the desired direction. Another compensating mechanism is the use of convergent eye movements, when horizontal gaze is attempted. Eye movements in the vertical plane are only mildly affected. The majority of patients suffer from a scoliosis that manifests itself in early infancy and usually requires operative treatment. Maldevelopment of neurons of the abducens nuclei and the caudal longitudinal fascicle is said to be the cause. The possible outcome of the disease and the importance of a prompt diagnosis are discussed.