Familial paralysis of horizontal gaze. Associated with pendular nystagmus, progressive scoliosis, and facial contraction with myokymia.

Paralysis of horizontal gaze, pendular nystagmus, and progressive scoliosis were manifestations of an autosomal recessive genetic disease in four siblings. Bilateral facial myokymia with continuous facial contraction developed in the oldest patient. Electromyographic examination of his facial muscles after facial nerve block at the stylomastoid foramen showed absence of all muscle potentials, consistent with a supranuclear origin of the myokymia. Normality of convergence, vertical gaze, and pupillary constrictor reflex activity assured integrity of midbrain ocular motor function. Absence of horizontal vestibulo-ocular reflexes signified involvement of the pontine tegmentum in this distinctive heredofamilial syndrome.