title: The importance of electrophysiology in revealing a complete homozygous deletion of KCNV2.
abstract: Visual electrophysiology is an important ancillary investigation in children with poor vision and nystagmus. Cone dystrophy with supranormal rod electroretinogram (KCNV2 retinopathy) has pathognomonic electrophysiology findings that, if identified, direct molecular genetic testing. We report the case of a 6-year-old boy with typical electrophysiology findings of KCNV2 retinopathy but with abnormal cone dysfunction compared to other patients with mutations in KCNV2. Molecular genetic testing revealed complete homozygous deletion of KCNV2. To our knowledge, this is the first such report. The greater cone dysfunction seen in this case suggests a phenotypic link to the genetic changes.
authors.affiliation: Save Sight Institute, Discipline of Ophthalmology, Sydney Eye Hospital Campus, The University of Sydney, Sydney, Australia. Electronic address: john.grigg@sydney.edu.au.
authors.forename: John R
authors.initials: JR
authors.lastname: Grigg
authors.forename: Graham E
authors.initials: GE
authors.lastname: Holder
authors.forename: Francis A
authors.initials: FA
authors.lastname: Billson
authors.forename: Maria
authors.initials: M
authors.lastname: Korsakova
authors.forename: Robyn V
authors.initials: RV
authors.lastname: Jamieson
mesh_terms: D002648:Child; D004596:Electroretinography; D017353:Gene Deletion; D006720:Homozygote; D006801:Humans; D008297:Male; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics*; D058499:Retinal Dystrophies / Q000235:genetics* / Q000503:physiopathology*; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*
chemical_list: C489610:KCNV2 protein, human; D024642:Potassium Channels, Voltage-Gated