title: Two sites in the MAPT region confer genetic risk for Guam ALS/PDC and dementia.
abstract: Unusual forms of amyotrophic lateral sclerosis (ALS-G), Parkinsonism dementia complex (PDC-G) and Guam dementia (GD) are found in Chamorros, the indigenous people of Guam. Neurofibrillary tangles composed of hyperphosphorylated tau are a neuropathologic feature of these closely related disorders. To determine if variation in the gene that encodes microtubule-associated protein tau gene (MAPT) contributes to risk for these disorders, we genotyped nine single nucleotide polymorphism (SNP) sites and one insertion/deletion in the 5' end of MAPT in 54 ALS-G, 135 PDC-G, 153 GD and 258 control subjects, all of whom are Chamorros. Variation at three SNPs (sites 2, 6 and 9) influenced risk for ALS-G, PDC-G and GD. SNP2 acts through a dominant mechanism and is independent of the risk conferred by SNPs 6 and 9, the latter two acting by a recessive mechanism. Persons with the high-risk SNP6 and SNP9 AC/AC diplotype had an increased risk of 3-fold [95% confidence interval (CI)=1.10-8.25] for GD, 4-fold (95% CI=1.40-11.64) for PDC-G and 6-fold (95% CI=1.44-32.14) for ALS-G, compared to persons with other diplotypes after adjusting for SNP2. Carriers of the SNP2 G allele had an increased risk of 1.6-fold (95% CI=1.00-2.62) for GD, 2-fold (95% CI=1.28-3.66) for PDC-G, and 1.5-fold (95% CI=0.74-3.00) for ALS-G, compared to non-carriers after adjusting for SNPs 6 and 9. Others have shown that SNP6 is also associated with risk for progressive supranuclear palsy. These two independent cis-acting sites presumably influence risk for Guam neuro-degenerative disorders by regulating MAPT expression.
authors.affiliation: Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA.
authors.forename: Purnima Desai
authors.initials: PD
authors.lastname: Sundar
authors.forename: Chang-En
authors.initials: CE
authors.lastname: Yu
authors.forename: Weiva
authors.initials: W
authors.lastname: Sieh
authors.forename: Ellen
authors.initials: E
authors.lastname: Steinbart
authors.forename: Ralph M
authors.initials: RM
authors.lastname: Garruto
authors.forename: Kiyomitsu
authors.initials: K
authors.lastname: Oyanagi
authors.forename: Ulla-Katrina
authors.initials: UK
authors.lastname: Craig
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Bird
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Wijsman
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Galasko
authors.forename: Gerard D
authors.initials: GD
authors.lastname: Schellenberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics*; D016022:Case-Control Studies; D002874:Chromosome Mapping; D002886:Chromosomes, Human, Pair 17; D003704:Dementia / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006141:Guam; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D020734:Parkinsonian Disorders / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors; D016875:tau Proteins / Q000235:genetics*
chemical_list: C054369:MAPT protein, human; D016875:tau Proteins