title: Deletion of the X-linked opsin gene array locus control region (LCR) results in disruption of the cone mosaic.
abstract: Blue cone monochromacy (BCM) is an X-linked condition in which long- (L) and middle- (M) wavelength-sensitive cone function is absent. Due to the X-linked nature of the condition, female carriers are spared from a full manifestation of the associated defects but can show visual symptoms, including abnormal cone electroretinograms. Here we imaged the cone mosaic in four females carrying an L/M array with deletion of the locus control region, resulting in an absence of L/M opsin gene expression (effectively acting as a cone opsin knockout). On average, they had cone mosaics with reduced density and disrupted organization compared to normal trichromats. This suggests that the absence of opsin in a subset of cones results in their early degeneration, with X-inactivation the likely mechanism underlying phenotypic variability in BCM carriers.
authors.affiliation: Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI 53226, United States. jcarroll@mcw.edu
authors.forename: Joseph
authors.initials: J
authors.lastname: Carroll
authors.forename: Ethan A
authors.initials: EA
authors.lastname: Rossi
authors.forename: Jason
authors.initials: J
authors.lastname: Porter
authors.forename: Jay
authors.initials: J
authors.lastname: Neitz
authors.forename: Austin
authors.initials: A
authors.lastname: Roorda
authors.forename: David R
authors.initials: DR
authors.lastname: Williams
authors.forename: Maureen
authors.initials: M
authors.lastname: Neitz
mesh_terms: D003117:Color Vision Defects / Q000235:genetics* / Q000473:pathology*; D055358:Cone Opsins / Q000235:genetics*; D004596:Electroretinography; D005260:Female; D017353:Gene Deletion; D006801:Humans; D010641:Phenotype; D016133:Polymerase Chain Reaction; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology*; D017422:Sequence Analysis, DNA
chemical_list: D055358:Cone Opsins