Cone Photoreceptor Structure in Patients With X-Linked Cone Dysfunction and Red-Green Color Vision Deficiency

Emily J Patterson, Melissa Wilk, Christopher S Langlo, Melissa Kasilian, Michael Ring, Robert B Hufnagel, Adam M Dubis, James J Tee, Angelos Kalitzeos, Jessica C Gardner, Zubair M Ahmed, Robert A Sisk, Michael Larsen, Stacy Sjoberg, Thomas B Connor, Alfredo Dubra, Jay Neitz, Alison J Hardcastle, Maureen Neitz, Michel MichaelidesJoseph Carroll

30 Citations (Scopus)

Abstract

PURPOSE: Mutations in the coding sequence of the L and M opsin genes are often associated with X-linked cone dysfunction (such as Bornholm Eye Disease, BED), though the exact color vision phenotype associated with these disorders is variable. We examined individuals with L/M opsin gene mutations to clarify the link between color vision deficiency and cone dysfunction.

METHODS: We recruited 17 males for imaging. The thickness and integrity of the photoreceptor layers were evaluated using spectral-domain optical coherence tomography. Cone density was measured using high-resolution images of the cone mosaic obtained with adaptive optics scanning light ophthalmoscopy. The L/M opsin gene array was characterized in 16 subjects, including at least one subject from each family.

RESULTS: There were six subjects with the LVAVA haplotype encoded by exon 3, seven with LIAVA, two with the Cys203Arg mutation encoded by exon 4, and two with a novel insertion in exon 2. Foveal cone structure and retinal thickness was disrupted to a variable degree, even among related individuals with the same L/M array.

CONCLUSIONS: Our findings provide a direct link between disruption of the cone mosaic and L/M opsin variants. We hypothesize that, in addition to large phenotypic differences between different L/M opsin variants, the ratio of expression of first versus downstream genes in the L/M array contributes to phenotypic diversity. While the L/M opsin mutations underlie the cone dysfunction in all of the subjects tested, the color vision defect can be caused either by the same mutation or a gene rearrangement at the same locus.

Original languageEnglish
JournalInvestigative ophthalmology & visual science
Volume57
Issue number8
Pages (from-to)3853-63
Number of pages11
ISSN0146-0404
DOIs
Publication statusPublished - 1 Jul 2016

Keywords

  • Journal Article

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