title: The patterns of inheritance in early-onset dementia: Alzheimer's disease and frontotemporal dementia.
abstract: OBJECTIVE
  To investigate the patterns of inheritance and gene mutation status in early-onset dementia (EOD).
  
  
  METHODS
  Data were collected on 202 consecutive patients presenting to an EOD clinic. Early-onset Alzheimer's disease (EOAD, n = 120) and early-onset frontotemporal dementia (EOFTD, n = 82) were studied.
  
  
  RESULTS
  The majority of participants, 72.5% with EOAD and 74.4% with EOFTD, did not have a positive family history of dementia. An autosomal dominant pattern of inheritance was observed in 14.2% of patients with EOAD and 13.4% of patients with FTD. Of those with an autosomal dominant pattern of inheritance, 11.8% of EOAD and 45.5% of FTD probands had known pathogenic mutations. Only 1.6% of the total population of EOAD and 7.3% of EOFTD possessed known gene mutations.
  
  
  CONCLUSIONS
  Early-onset dementia does not appear to be a strongly inherited autosomal dominant condition. The majority of patients were sporadic. Known mutations were uncommon and do not explain the total autosomal dominant burden.
authors.affiliation: Neurodegenerative Disorders Research Pty Ltd, Subiaco, West Perth, Australia.
authors.forename: Anna I
authors.initials: AI
authors.lastname: Jarmolowicz
authors.affiliation: Neurodegenerative Disorders Research Pty Ltd, Subiaco, West Perth, Australia.
authors.forename: Huei-Yang
authors.initials: HY
authors.lastname: Chen
authors.affiliation: Neurodegenerative Disorders Research Pty Ltd, Subiaco, West Perth, Australia research@ndr.org.au.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Panegyres
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000544:Alzheimer Disease / Q000235:genetics*; D015331:Cohort Studies; D005260:Female; D057180:Frontotemporal Dementia / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: Alzheimer’s disease; early onset dementia; family history; frontotemporal dementia; genes and dementia