Familial Multiple Sclerosis Associated With Narcolepsy

THE INVESTIGATIONS of Curtius¹and Mackay²focused increasing interest on the familial occurrence of multiple sclerosis (MS). Several studies have been reported in recent years.³⁻⁷In large series of multiple sclerosis, the incidence of the familial form has ranged from 3% to 12%.⁸The risk of contracting the disease is stated to be more than 15 times greater in a close relative of a patient with MS than in the general population.⁸It therefore seems reasonable to presume that hereditary factors are of etiological importance. Myrianthopoulos and Mackay⁶suggested that the mode of inheritance is autosomal recessive with reduced penetrance. Studies of monozygotic twins have, on the other hand, shown low concordance for MS.⁵,⁹,¹⁰This has been used as an argument against genetic factors being of any decisive consequence.¹⁰ This paper comprises a report of a form of familial MS associated