title: Copy-number variations in EYS: a significant event in the appearance of arRP.
abstract: OBJECTIVE
  Autosomal recessive retinitis pigmentosa (arRP) has recently been associated with mutations in a novel gene, EYS, which is a major gene for this disease. All published mutations so far are based on conventional PCR and are not adequate to identify midsized DNA rearrangements. This study was conducted to establish the prevalence of copy-number variations (CNVs) in the EYS gene in a cohort of arRP patients, including individuals in whom only one pathogenic change was detected by PCR-based sequencing.
  
  
  METHODS
  A multiple ligation-dependent probe amplification (MLPA) was used for the molecular genetic analyses of CNVs by a novel EYS-specific kit. PCR-based direct sequencing was used in families where a pathogenic deletion or duplication was identified in one allele. Bioinformatics analyses was undertaken to study the effect of the mutations on protein structure and function.
  
  
  RESULTS
  Six novel pathogenic CNVs were identified. Also, the presence of four midsized deletions was confirmed in patients previously identified. Midsized genomic rearrangements in EYS are disease causing in ∼4% of the families with no reported mutations and constitute the second pathogenic variation in ∼15% of cases where a mutation has been detected by direct sequencing.
  
  
  CONCLUSIONS
  This is the first report of a systematic CNV screening of EYS gene in a cohort of arRP patients. Results suggest that midsized genomic rearrangements in EYS gene would be a common event in the appearance of RP phenotype. An efficient and cost-effective strategy validating a novel MLPA kit as a complementary diagnostic method for EYS pathogenic evaluation has been demonstrated.
authors.affiliation: Unidad de Gestión Clínica de Genética, Reproducción y Medicina Fetal, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Juan I
authors.initials: JI
authors.lastname: Pieras
authors.forename: Isabel
authors.initials: I
authors.lastname: Barragán
authors.forename: Salud
authors.initials: S
authors.lastname: Borrego
authors.forename: Isabelle
authors.initials: I
authors.lastname: Audo
authors.forename: María
authors.initials: M
authors.lastname: González-Del Pozo
authors.forename: Sara
authors.initials: S
authors.lastname: Bernal
authors.forename: Montserrat
authors.initials: M
authors.lastname: Baiget
authors.forename: Christina
authors.initials: C
authors.lastname: Zeitz
authors.forename: Shomi S
authors.initials: SS
authors.lastname: Bhattacharya
authors.forename: Guillermo
authors.initials: G
authors.lastname: Antiñolo
mesh_terms: D001483:Base Sequence; D015342:DNA Probes; D005136:Eye Proteins / Q000235:genetics*; D005192:Family Health; D005260:Female; D005602:France / Q000453:epidemiology; D017353:Gene Deletion; D018628:Gene Dosage / Q000235:genetics*; D015321:Gene Rearrangement; D005808:Genes, Recessive; D005820:Genetic Testing / Q000379:methods / Q000592:standards; D014644:Genetic Variation; D006801:Humans; D008297:Male; D010641:Phenotype; D017354:Point Mutation; D015995:Prevalence; D015203:Reproducibility of Results; D012174:Retinitis Pigmentosa / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology; D013030:Spain / Q000453:epidemiology
chemical_list: D015342:DNA Probes; C533105:EYS protein, human; D005136:Eye Proteins