Familial congenital fourth cranial nerve palsy.

Few reports of hereditary transmission patterns in congenital superior oblique palsy have been made in the past. In this study, three families with congenital superior oblique palsies have been identified and examined. Two members of each family had a superior oblique palsy. After full history, eye examination, and sensory testing, the patterns in each family have been analyzed. Deviations varied from binocular fusion and orthophoria to large vertical deviations, especially in adduction. Sensory patterns were compatible with the congenital nature of the palsy. A discussion of possible causes for a congenital superior oblique palsy is offered and the congenital superior oblique palsies are analyzed. A definite genetic transmission pattern could not be found, but possible explanations are considered. Regardless of etiology, therapy for this problem is unchanged from that for all superior oblique palsies. Occurrences of congenital trochlear palsies in multiple family members should be considered when a patient with this problem is diagnosed.