title: Targeted next-generation sequencing of a 12.5 Mb homozygous region reveals ANO10 mutations in patients with autosomal-recessive cerebellar ataxia.
abstract: Autosomal-recessive cerebellar ataxias comprise a clinically and genetically heterogeneous group of neurodegenerative disorders. In contrast to their dominant counterparts, unraveling the molecular background of these ataxias has proven to be more complicated and the currently known mutations provide incomplete coverage for genotyping of patients. By combining SNP array-based linkage analysis and targeted resequencing of relevant sequences in the linkage interval with the use of next-generation sequencing technology, we identified a mutation in a gene and have shown its association with autosomal-recessive cerebellar ataxia. In a Dutch consanguineous family with three affected siblings a homozygous 12.5 Mb region on chromosome 3 was targeted by array-based sequence capture. Prioritization of all detected sequence variants led to four candidate genes, one of which contained a variant with a high base pair conservation score (phyloP score: 5.26). This variant was a leucine-to-arginine substitution in the DUF 590 domain of a 16K transmembrane protein, a putative calcium-activated chloride channel encoded by anoctamin 10 (ANO10). The analysis of ANO10 by Sanger sequencing revealed three additional mutations: a homozygous mutation (c.1150_1151del [p.Leu384fs]) in a Serbian family and a compound-heterozygous splice-site mutation (c.1476+1G>T) and a frameshift mutation (c.1604del [p.Leu535X]) in a French family. This illustrates the power of using initial homozygosity mapping with next-generation sequencing technology to identify genes involved in autosomal-recessive diseases. Moreover, identifying a putative calcium-dependent chloride channel involved in cerebellar ataxia adds another pathway to the list of pathophysiological mechanisms that may cause cerebellar ataxia.
authors.affiliation: Department of Human Genetics, Radboud University Nijmegen Medical Centre, The Netherlands. s.vermeer@antrg.umcn.nl
authors.forename: Sascha
authors.initials: S
authors.lastname: Vermeer
authors.forename: Alexander
authors.initials: A
authors.lastname: Hoischen
authors.forename: Rowdy P P
authors.initials: RP
authors.lastname: Meijer
authors.forename: Christian
authors.initials: C
authors.lastname: Gilissen
authors.forename: Kornelia
authors.initials: K
authors.lastname: Neveling
authors.forename: Nienke
authors.initials: N
authors.lastname: Wieskamp
authors.forename: Arjan
authors.initials: A
authors.lastname: de Brouwer
authors.forename: Michel
authors.initials: M
authors.lastname: Koenig
authors.forename: Mathieu
authors.initials: M
authors.lastname: Anheim
authors.forename: Mirna
authors.initials: M
authors.lastname: Assoum
authors.forename: Nathalie
authors.initials: N
authors.lastname: Drouot
authors.forename: Slobodanka
authors.initials: S
authors.lastname: Todorovic
authors.forename: Vedrana
authors.initials: V
authors.lastname: Milic-Rasic
authors.forename: Hanns
authors.initials: H
authors.lastname: Lochmüller
authors.forename: Giovanni
authors.initials: G
authors.lastname: Stevanin
authors.forename: Cyril
authors.initials: C
authors.lastname: Goizet
authors.forename: Albert
authors.initials: A
authors.lastname: David
authors.forename: Alexandra
authors.initials: A
authors.lastname: Durr
authors.forename: Alexis
authors.initials: A
authors.lastname: Brice
authors.forename: Berry
authors.initials: B
authors.lastname: Kremer
authors.forename: Bart P C
authors.initials: BP
authors.lastname: van de Warrenburg
authors.forename: Mascha M V A P
authors.initials: MM
authors.lastname: Schijvenaars
authors.forename: Angelien
authors.initials: A
authors.lastname: Heister
authors.forename: Michael
authors.initials: M
authors.lastname: Kwint
authors.forename: Peer
authors.initials: P
authors.lastname: Arts
authors.forename: Jenny
authors.initials: J
authors.lastname: van der Wijst
authors.forename: Joris
authors.initials: J
authors.lastname: Veltman
authors.forename: Erik-Jan
authors.initials: EJ
authors.lastname: Kamsteeg
authors.forename: Hans
authors.initials: H
authors.lastname: Scheffer
authors.forename: Nine
authors.initials: N
authors.lastname: Knoers
mesh_terms: D000075369:Anoctamin-1; D002524:Cerebellar Ataxia / Q000235:genetics*; D018118:Chloride Channels; D005808:Genes, Recessive; D006720:Homozygote; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide
chemical_list: C476213:ANO1 protein, human; D000075369:Anoctamin-1; D018118:Chloride Channels; D008565:Membrane Proteins; D009363:Neoplasm Proteins