Six members of a family--the mother, three daughters, and two sons--have a unique syndrome consisting of congenital external ophthalmoplegia, bilateral facial weakness, lingua scrotalis, progressive chorioretinal sclerosis, and an intellectual deficit. Bilateral ptosis and almost complete ophthalmoplegia were found in three of the family members, bilateral facial weakness in two, and Parinaud's syndrome and convergence paresis in one. Electromyographically, a lesion of the lower motor neurons--"nuclear ophthalmoplegia"--was found. Three members of the family had different stages of progressive chorioretinal sclerosis and two had myopia. All the family members had lingua scrotalis, and all of those who had ophthalmoplegia had low IQs. Electroretinographic reactions were subnormal or absent in patients with chorioretinal degeneration. It was concluded that an extensive abiotrophic process, genetically conditioned, was a possibility.