title: No evidence for genetic association or linkage of the cathepsin D (CTSD) exon 2 polymorphism and Alzheimer disease.
abstract: Two recent case-control studies have suggested a strong association of a missense polymorphism in exon 2 of the cathepsin D gene (CTSD) and Alzheimer disease (AD). However, these findings were not confirmed in another independent study. We analyzed this polymorphism in two large and independent AD study populations and did not detect an association between CTSD and AD. The first sample was family-based and included 436 subjects from 134 sibships discordant for AD that were analyzed using the sibship disequilibrium test (SDT, p = 0.68) and the sib transmission/disequilibrium test (Sib-TDT, p = 0.81). The second sample of 200 AD cases and 182 cognitively normal controls also failed to show significant differences in the allele or genotype distribution in cases versus controls (chi2, p = 0.91 and p = 0.88, respectively). In addition, two-point linkage analyses in an enlarged family sample (n = 670) did not show evidence for linkage of the chromosomal region around CTSD. Thus, our analyses on more than 800 subjects suggest that if an association between the CTSD exon 2 polymorphism and AD exists, it is likely to be smaller than previously reported.
authors.affiliation: Genetics and Aging Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, USA.
authors.forename: L
authors.initials: L
authors.lastname: Bertram
authors.forename: S
authors.initials: S
authors.lastname: Guénette
authors.forename: J
authors.initials: J
authors.lastname: Jones
authors.forename: D
authors.initials: D
authors.lastname: Keeney
authors.forename: K
authors.initials: K
authors.lastname: Mullin
authors.forename: A
authors.initials: A
authors.lastname: Crystal
authors.forename: S
authors.initials: S
authors.lastname: Basu
authors.forename: S
authors.initials: S
authors.lastname: Yhu
authors.forename: A
authors.initials: A
authors.lastname: Deng
authors.forename: G W
authors.initials: GW
authors.lastname: Rebeck
authors.forename: B T
authors.initials: BT
authors.lastname: Hyman
authors.forename: R
authors.initials: R
authors.lastname: Go
authors.forename: M
authors.initials: M
authors.lastname: McInnis
authors.forename: D
authors.initials: D
authors.lastname: Blacker
authors.forename: R
authors.initials: R
authors.lastname: Tanzi
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000235:genetics*; D016022:Case-Control Studies; D002402:Cathepsin D / Q000235:genetics*; D005091:Exons / Q000235:genetics; D008040:Genetic Linkage / Q000235:genetics*; D005838:Genotype; D006801:Humans; D011110:Polymorphism, Genetic / Q000235:genetics*
chemical_list: D002402:Cathepsin D