CNGB3 mutations cause severe rod dysfunction
| Autor: | Martin McKibbin, Declan J. McKeefry, Kamron N. Khan, James H. Maguire, Susanne Kohl, Manir Ali |
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| Rok vydání: | 2017 |
| Předmět: |
Adult
Male 0301 basic medicine medicine.medical_specialty Achromatopsia genetic structures Cyclic Nucleotide-Gated Cation Channels Rod monochromatism Color Vision Defects Dark Adaptation 030105 genetics & heredity Consanguinity Macular Degeneration 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Retinal Rod Photoreceptor Cells Ophthalmology Electroretinography medicine Humans Scotopic vision Genetics (clinical) medicine.diagnostic_test business.industry Siblings Retinal Full field medicine.disease eye diseases chemistry Mutation Pediatrics Perinatology and Child Health 030221 ophthalmology & optometry Clinical electrophysiology Female sense organs business Erg Photic Stimulation |
| Zdroj: | Ophthalmic Genetics. 39:108-114 |
| ISSN: | 1744-5094 1381-6810 |
| Popis: | Congenital achromatopsia or rod monochromatism is a rare autosomal recessive condition defined by a severe loss of cone photoreceptor function in which rods purportedly retain normal or near-to-normal function. This report describes the results of electroretinography in two siblings with CNGB3-associated achromatopsia.Full field light- and dark-adapted electroretinograms (ERGs) were recorded using standard protocols detailed by the International Society for Clinical Electrophysiology of Vision (ISCEV). We also examined rod-mediated ERGs using series of stimuli that varied over a 6 log unit range of retinal illuminances (-1.9-3.5 log scotopic trolands).Dark-adapted ERGs in achromatopsia patients exhibited severely reduced b-wave amplitudes with abnormal b:a ratios (1.3 and 0.6). In comparison, the reduction in a-wave amplitude was less marked. The rod-mediated ERG took on an electronegative appearance at high-stimulus illuminances.Although the defect that causes achromatopsia is primarily in the cone photoreceptors, our results reveal an accompanying disruption of rod function that is more severe than has previously been reported. The differential effects on the b-wave relative to the a-wave points to an inner-retinal locus for the disruption of rod function in these patients. |
| Databáze: | OpenAIRE |
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