In vivo imaging of the photoreceptor mosaic of a rod monochromat.

Abstract

Complete achromatopsia (i.e., rod monochromacy) is a congenital vision disorder in which cone function is absent or severely diminished, often due to mutations in one of two components of the cone phototransduction cascade (transducin or the cyclic-nucleotide gated channel). Previous histological data concerning cone structure are conflicting; suggesting anywhere from normal numbers of foveal cones to a complete absence of foveal cones. Here, we used an adaptive optics ophthalmoscope to obtain in vivo retinal images from a rod monochromat for whom the genetic basis of the disorder consists of a homozygous mutation in the CNGB3 gene. Behavioral data from the patient were consistent with an absence of cone function. Retinal images revealed a severely disrupted photoreceptor mosaic in the fovea and parafovea, where the size and density of the visible photoreceptors resembled that of normal rods. Imaging of additional rod monochromats to characterize differences in the photoreceptor mosaic between genetically classified patients will be required to determine which, if any, might be receptive to restorative gene therapy procedures.

• Authors: Joseph Carroll, Stacey S Choi, David R Williams
• Journal: Vision research (Vision Res) Vol. 48 Issue 26 Pg. 2564-8 (Nov 2008) ISSN: 1878-5646 [Electronic] England
• PMID: 18499214 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• CNGB3 protein, human
• Cyclic Nucleotide-Gated Cation Channels

Topics

• Adult
• Cell Size
• Color Vision Defects (genetics, pathology)
• Cyclic Nucleotide-Gated Cation Channels (genetics)
• Female
• Humans
• Male
• Middle Aged
• Mutation
• Ophthalmoscopy (methods)
• Phenotype
• Retinal Cone Photoreceptor Cells (pathology)
• Retinal Rod Photoreceptor Cells (pathology)