CLINICAL DEMOGRAPHICS OF MULTIPLEX FAMILIES WITH MULTIPLE-SCLEROSIS

The demographic and clinical characteristics of 89 multiplex families whose affected members meet proposed diagnostic criteria for multiple sclerosis (MS) genetic research are described and compared with 425 sp oradic cases of MS and other published collections of MS multiplex fam ilies. The proportion of affected multiplex family members who experie nced gradual progression of disability from onset (primary progressive MS) is lower than reported by other investigators. Different phenotyp es of MS may reflect genetic heterogeneity that may partially explain inconsistencies in the results of genetic linkage studies. Clinical de tails of affected multiplex family members must be described so that c omparisons of genetic results across studies can be properly interpret ed.