title: SPG4 founder effect in French Canadians with hereditary spastic paraplegia.
abstract: BACKGROUND
  The most common cause of autosomal dominant Hereditary Spastic Paraplegia (HSP) is mutations in the SPG4 gene. We have previously identified novel SPG4 mutations in a collection of North American families including the c.G1801A mutation present in two families from Quebec. The aim of this study is to estimate the frequency of the c.G1801A mutation in the French Canadian (FC) population and to determine whether this mutation originates from a common ancestor.
  
  
  METHODS
  We collected and sequenced exon 15 in probands of 37 families. Genotypes of markers flanking the SPG4 gene were used to construct haplotypes in five families. Clinical information was reviewed by a neurologist with expertise in HSP.
  
  
  RESULTS
  We have identified three additional unrelated families with the c.G1801A mutation and haplotype analysis revealed that all five families share a common ancestor. The mutation is present in 7% of all our FC families and explains half of our spastin linked FC families. The phenotype associated with the c.G1801A genotype is pure HSP with bladder involvement.
  
  
  CONCLUSIONS
  In this study we have determined that the relative frequency of the c.G1801A mutation in our FC collection is 7%, and approximately 50% in the spastin positive FC group. This mutation is the most common HSP mutation identified in this population to date and is suggestive of a founder effect in Quebec.
authors.affiliation: Center for the Study of Brain Diseases, CHUM Research Center, Notre-Dame Hospital, Montreal, QC, Canada.
authors.forename: Inge A
authors.initials: IA
authors.lastname: Meijer
authors.forename: Nicolas
authors.initials: N
authors.lastname: Dupré
authors.forename: Bernard
authors.initials: B
authors.lastname: Brais
authors.forename: Patrick
authors.initials: P
authors.lastname: Cossette
authors.forename: Judith
authors.initials: J
authors.lastname: St-Onge
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Rioux
authors.forename: Melanie
authors.initials: M
authors.lastname: Benard
authors.forename: Guy A
authors.initials: GA
authors.lastname: Rouleau
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D018703:Founder Effect; D005602:France / Q000208:ethnology; D005787:Gene Frequency; D006239:Haplotypes; D006801:Humans; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D010375:Pedigree; D011792:Quebec; D015419:Spastic Paraplegia, Hereditary / Q000208:ethnology / Q000235:genetics*; D000074181:Spastin; D044465:White People / Q000235:genetics*
chemical_list: D000251:Adenosine Triphosphatases; D000074181:Spastin; C400283:SPAST protein, human