Contingent negative variation in subjects at risk for migraine without aura

Migraine is a complex disease with a significant genetic background. One po ssible strategy to investigate the genetics of migraine is the evaluation o f functional vulnerability markers or biological elementary endophenotypes in individuals with the greatest probability of developing the disorder (hi gh-risk design). In this study the contingent negative variation (CNV) was recorded in 35 high-risk subjects with a positive family history of migrain e without aura (FHP), 35 low-risk individuals without a positive family his tory (FHN), and 35 migraineurs (migraine without aura). FHP subjects and mi graine patients differed significantly from FHN individuals with regard to amplitude and habituation slope of the early CNV component (initial CNV or iCNV). FHP participants demonstrated the same iCNV abnormalities and distri bution among iCNV characteristics as migraineurs. The amplitude of the iCNV correlated significantly with the relative number of subjects suffering fr om migraine among first- and second-degree relatives. The higher the densit y of affected individuals in the family, the more pronounced were the CN-V abnormalities in relatives. This study provides evidence that the familial factor contributes to the abnormal amplitude, and to a lesser degree, habit uation of the iCNV, and that the iCNV may be used as a functional-genetic v ulnerability marker in further research of migraine genetics. (C) 2001 Publ ished by Elsevier Science B.V. on behalf of International Association for t he Study of Pain.