title: Absence of consensus in diagnostic criteria for familial neurodegenerative diseases.
abstract: BACKGROUND
  A small proportion of cases seen in neurodegenerative conditions such as amyotrophic lateral sclerosis (ALS), Parkinson's disease and Alzheimer disease are familial. These familial cases are usually clinically indistinguishable from sporadic cases. Identifying familial cases is important both in terms of clinical guidance for family members and for gene discovery.
  
  
  METHODS
  Surveys assessing the definition of familial amyotrophic lateral sclerosis (FALS) were completed by clinicians with an interest in ALS.
  
  
  RESULTS
  95 surveys were completed by respondents from 15 countries. A third of total respondents stated that they thought that neurologists were using the same definition for FALS (33.3%, 30). No consensus was achieved among clinicians when provided with five different definitions for FALS. However, the preferred definition was 'a patient with ALS with either a first or second degree relative also with ALS' (37.8%, 31).
  
  
  CONCLUSIONS
  There is no consensus on a standard definition for FALS among clinicians. It is likely that similar inconsistencies apply to other conditions, such as Parkinson's disease and Alzheimer disease, in which both familial and sporadic diseases occur. Inconsistent classification could hinder gene discovery.
authors.affiliation: Trinity College Institute of Neurosciences, Beaumont Hospital, Trinity College, Dublin, Ireland. suabyrne@gmail.com
authors.forename: Susan
authors.initials: S
authors.lastname: Byrne
authors.forename: Marwa
authors.initials: M
authors.lastname: Elamin
authors.forename: Peter
authors.initials: P
authors.lastname: Bede
authors.forename: Orla
authors.initials: O
authors.lastname: Hardiman
mesh_terms: D000544:Alzheimer Disease / Q000175:diagnosis / Q000235:genetics; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis / Q000235:genetics; D001315:Australia; D003937:Diagnosis, Differential; D005060:Europe; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D009154:Mutation; D019636:Neurodegenerative Diseases / Q000175:diagnosis* / Q000235:genetics*; D009462:Neurology / Q000295:instrumentation / Q000592:standards*; D009656:North America; D010300:Parkinson Disease / Q000175:diagnosis / Q000235:genetics; D011159:Population Surveillance; D010818:Practice Patterns, Physicians' / Q000592:standards / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires