title: Familial aggregation of early- and late-onset Parkinson's disease.
abstract: The role of heredity in early- versus late-onset Parkinson's disease (PD) is controversial. We estimated the degree of increased risk of PD in first-degree relatives of 221 PD probands with age of onset 50 years or younger and 266 PD probands with age of onset older than 50 years compared with the first-degree relatives of 409 control probands. Risk of PD was similar among first-degree relatives of early-onset PD probands (risk ratio [RR], 2.9; 95% confidence interval [CI], 1.6-5.0; p = 0.0002) and late-onset PD probands (RR, 2.7; 95% CI, 1.6-4.4; p = 0.0002) when each was compared with first-degree relatives of controls. However, siblings of early-onset PD probands were at markedly increased risk of PD compared with siblings of controls (RR, 7.9; 95% CI, 2.5-25.5; p = 0.0005), whereas parents of early-onset PD probands were not at significantly increased risk compared with parents of controls (RR, 1.7; 95% CI, 0.9-3.3; p = 0.2). In late-onset families, both siblings (RR, 3.6; 95% CI, 1.3-10.3; p = 0.02) and parents (RR, 2.5; 95% CI, 1.4-4.6; p = 0.003) were at increased risk compared with control relatives. This pattern is consistent with an autosomal recessive contribution to the inheritance of early but not late-onset PD. Genetic factors are important in both early- and late-onset PD, but specific genes and mode of inheritance may differ between the two groups.
authors.affiliation: Department of Neurology, Columbia University, New York, NY, USA. ksm1@columbia.edu
authors.forename: Karen
authors.initials: K
authors.lastname: Marder
authors.forename: Gilberto
authors.initials: G
authors.lastname: Levy
authors.forename: Elan D
authors.initials: ED
authors.lastname: Louis
authors.forename: Helen
authors.initials: H
authors.lastname: Mejia-Santana
authors.forename: Lucien
authors.initials: L
authors.lastname: Cote
authors.forename: Howard
authors.initials: H
authors.lastname: Andrews
authors.forename: Juliette
authors.initials: J
authors.lastname: Harris
authors.forename: Cheryl
authors.initials: C
authors.lastname: Waters
authors.forename: Blair
authors.initials: B
authors.lastname: Ford
authors.forename: Steven
authors.initials: S
authors.lastname: Frucht
authors.forename: Stanley
authors.initials: S
authors.lastname: Fahn
authors.forename: Ruth
authors.initials: R
authors.lastname: Ottman
mesh_terms: D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D003710:Demography; D005190:Family; D005192:Family Health; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D010300:Parkinson Disease / Q000453:epidemiology / Q000235:genetics*; D012307:Risk Factors; D011795:Surveys and Questionnaires; D016019:Survival Analysis