Journal article

Publication year: 2011

Pages: 8621-8629

Journal: Investigative ophthalmology & visual science

Volume number: 52

Issue number: 12

ISSN: 0146-0404

eISSN: 1552-5783

DOI Link: https://doi.org/10.1167/iovs.11-8187

Publisher: Association for Research in Vision and Ophthalmology

Abstract: 
PURPOSE. To provide an up to 14-year overview of the early ocular phenotype in siblings with a homozygous p.G461R mutation in the KCNV2 gene. METHODS. Two brothers and their sister were followed-up clinically from ages 5 years, 4 years, and 2 months, respectively, including complete ophthalmological examinations. Gold-mann visual fields, two-color-threshold (2CT) perimetry, color vision testing, optical coherence tomography (OCT), fundus autofluorescence (FAF), and Ganzfeld electroretinograms (ERGs) were performed according to age-related capabilities. Genetic analyses included whole genome linkage analysis, homozygosity mapping, and candidate gene sequencing. RESULTS. All three siblings were homozygous for the p.G461R mutation. At 5 months, the younger brother had no nystagmus and Teller-acuity of 3.2 cyc/deg. At older age, all three presented nystagmus, increased light sensitivity, reduced color discrimination, and relative central scotomas. Visual acuities ranged from 20/200 to 20/70. The macula developed minor irregularities of the RPE, thinning in optical coherence tomography, and a ring of increased FAF. Scotopic (rod) sensitivity was reduced by 2 log and photopic sensitivity by 1 log in two-color-threshold perimetry. ERG responses were markedly delayed. Photopic amplitudes were severely reduced. Scotopic b-waves rose steeply with flash intensity, but for the standard flash supernormal amplitudes were only reached in the girl. CONCLUSIONS. FAF was similar to that in cone-rod dystrophy. Although cone dysfunction was accompanied by rod dysfunction, and scotopic ERGs in patient 2 deteriorated, no patient demonstrated any unequivocal sign of rod degeneration. Grossly delayed b-waves with a steep response-versus-intensity relationship rather than supernormal amplitudes should remind clinicians of this specific condition. (Invest Ophthalmol Vis Sci. 2011;52:8621-8629) DOI: 10.1167/iovs.11-8187

Harvard Citation style: Friedburg, C., Wissinger, B., Schambeck, M., Bonin, M., Kohl, S. and Lorenz, B. (2011) Long-Term Follow-Up of the Human Phenotype in Three Siblings with Cone Dystrophy Associated with a Homozygous p.G461R Mutation of KCNV2, Investigative ophthalmology & visual science, 52(12), pp. 8621-8629. https://doi.org/10.1167/iovs.11-8187

APA Citation style: Friedburg, C., Wissinger, B., Schambeck, M., Bonin, M., Kohl, S., & Lorenz, B. (2011). Long-Term Follow-Up of the Human Phenotype in Three Siblings with Cone Dystrophy Associated with a Homozygous p.G461R Mutation of KCNV2. Investigative ophthalmology & visual science. 52(12), 8621-8629. https://doi.org/10.1167/iovs.11-8187