title: DNA analysis of Huntington's disease: five years of experience in Germany, Austria, and Switzerland.
abstract: OBJECTIVE
  To review the direct DNA testing for Huntington's disease (HD) in Germany, Switzerland, and Austria from 1993 to 1997, and to analyze the population with regard to age structure, gender, and family history.
  
  
  METHODS
  Twelve laboratories (nine in Germany, two in Austria, and one in Switzerland) recorded data pertaining to repeat number, gender, age at molecular diagnosis, and family history of probands. The molecular test was categorized as either diagnostic (for symptomatic individuals), presymptomatic (for individuals at risk), and prenatal (for pregnancies at risk).
  
  
  RESULTS
  A total of 3,090 HD patients, 992 individuals at risk, and 24 fetuses were investigated using DNA analysis. The clinical diagnosis was confirmed in 65.6% of patients. A total of 38.5% of individuals at risk inherited an expanded CAG repeat. The female-to-male ratio showed a distinct predominance of women both in the diagnostic and presymptomatic groups. Of the fetuses tested, six were carriers of an expanded CAG repeat. Two pregnancies were interrupted; one pregnancy was not. No information about the parents' decision was obtained for the remaining three pregnancies.
  
  
  CONCLUSIONS
  Approximately 20% of the estimated 10,000 HD patients living in Germany, Switzerland, and Austria have been identified by DNA analysis (total population, approximately 100 million; incidence of HD, 1:10,000). Assuming a ratio of HD patients to individuals at risk of 1:3, approximately 30,000 individuals are, in principle, eligible for a presymptomatic test. Less than 3 to 4% of individuals at risk have requested a presymptomatic test. This shows that the assumed enormous request of predictive testing has not occurred. More surprisingly, prenatal diagnoses were found to be rare.
authors.affiliation: Institute of Human Genetics, University of Göttingen, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Laccone
authors.forename: U
authors.initials: U
authors.lastname: Engel
authors.forename: E
authors.initials: E
authors.lastname: Holinski-Feder
authors.forename: M
authors.initials: M
authors.lastname: Weigell-Weber
authors.forename: K
authors.initials: K
authors.lastname: Marczinek
authors.forename: D
authors.initials: D
authors.lastname: Nolte
authors.forename: D J
authors.initials: DJ
authors.lastname: Morris-Rosendahl
authors.forename: C
authors.initials: C
authors.lastname: Zühlke
authors.forename: K
authors.initials: K
authors.lastname: Fuchs
authors.forename: H
authors.initials: H
authors.lastname: Weirich-Schwaiger
authors.forename: G
authors.initials: G
authors.lastname: Schlüter
authors.forename: G
authors.initials: G
authors.lastname: von Beust
authors.forename: A M
authors.initials: AM
authors.lastname: Vieira-Saecker
authors.forename: B H
authors.initials: BH
authors.lastname: Weber
authors.forename: O
authors.initials: O
authors.lastname: Riess
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D001317:Austria; D004247:DNA / Q000032:analysis*; D005260:Female; D005858:Germany; D006801:Humans; D006816:Huntington Disease / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013557:Switzerland; D020080:Tandem Repeat Sequences
chemical_list: D004247:DNA