title: Concordance of common movement disorders among familial cases.
abstract: Multicase families are frequently utilized in studies of movement disorders (MDs). We report families with two or more MD cases seen at the Movement Disorder Clinic, Saskatoon (MDCS). In 30% of the MD probands, there was either a history or documentation of at least one secondary MD case in the family. Only those MD cases that were seen at the MDCS were considered in this study. A total of 56 probands and 77 secondary MD cases were seen at the MDCS between 1968 and 1996. In 24 (31.2%) of the secondary cases, the diagnosis was different from that in the proband. In 46 families (82%), only one secondary case was seen, and the diagnosis was concordant with the proband in 71.7%. In the remaining 10 families with two or more secondary cases, the diagnosis was concordant in 64.5% of cases. The largest subgroup was Parkinson's disease (PD)--40 probands and 53 secondary cases. of these secondary cases, 73.6% had PD. The concordance rate was 91% in essential tremor, but only 12.5% if the proband had essential tremor + parkinsonism. Considering that a large proportion of secondary cases have a diagnosis discordant with the proband, we recommend that, whenever possible, MD diagnosis in secondary cases be based on clinical assessment.
authors.affiliation: Division of Neurology, University of Saskatchewan, Saskatoon, Canada.
authors.forename: A H
authors.initials: AH
authors.lastname: Rajput
authors.forename: M E
authors.initials: ME
authors.lastname: Fenton
authors.forename: D
authors.initials: D
authors.lastname: George
authors.forename: A
authors.initials: A
authors.lastname: Rajput
authors.forename: W
authors.initials: W
authors.lastname: Wilson
authors.forename: L
authors.initials: L
authors.lastname: McCulloch
mesh_terms: D017668:Age of Onset; D000368:Aged; D018450:Disease Progression; D005192:Family Health; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000188:drug therapy / Q000235:genetics*; D010300:Parkinson Disease / Q000188:drug therapy / Q000235:genetics; D012189:Retrospective Studies; D012525:Saskatchewan; D013132:Spinocerebellar Degenerations / Q000188:drug therapy / Q000235:genetics; D013494:Supranuclear Palsy, Progressive / Q000188:drug therapy / Q000235:genetics; D014202:Tremor / Q000188:drug therapy / Q000235:genetics