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Sung Eun Song Watanabe, Daniel M Rocha, Paula Y Sacai, Gabriel I Botelho, Juliana Freire Bueno, Alcides Barros-Filho, Solange Rios Salomao, Adriana Berezovsky; Long-term follow-up from a family with X-linked cone dystrophy phenotype. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5963. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Progressive cone dystrophy is characterized by reduction of visual acuity, loss of central vision, color vision impairment in late childhood or early adulthood. The age of onset and rate of progression of symptoms can vary. Inheritance pattern is usually recessive, autosomal dominant and rarely X-linked. We describe the long-term outcomes of three members from a family with X-linked cone dystrophy.
Three men of the same family including 2 siblings (cases #1 and #2) and 1 cousin case #3) were referred for electrophysiological testing due to visual acuity reduction, photophobia and color vision loss. Visual acuity (VA), color fundus imaging, SD-OCT and full-field electroretinography (ERG) were performed. Electrophysiology study from each visit was analyzed as well as longitudinal clinical characteristics after a long follow-up period (from 7 years in cases #1 and #2 to 19 years in case #3).
A pedigree based on their personal and family history was built and it was consistent with X-linked inheritance. In all cases the vision loss was present in the first decade of life. In all subjects, decreased visual acuity, high myopia (<6.0 D spherical equivalent) and myopic fundus were detected. Nystagmus was present only in case #3. SD-OCT revealed macular changes as absence of ellipsoid zone in foveal area and thinned outer retinal layer (outer nuclear layer, external limiting membrane, photoreceptor and RPE) and ERG analysis showed evidence for severe generalized cone system dysfunction and normal rod function in all affected along time. Dark-adapted thresholds psychophysically determined were normal in all cases in the first and last visits. In case #3 a negative ERG was present with b/a ratio ranging from 1.09 in the first visit to 1.06 in the last visit. VA in the better-seeing eye was stable, with values initially around 20/125 and 20/160 in the last visit. The refractive errors according to first and last visit were high myopia, ranging from -6.5 to -9.5 D of spherical equivalent.
Herein we presented members of the same family with similar characteristics of X-linked cone dystrophy phenotype, with emphasis on stable findings considering loss of visual acuity, non-detectable photopic ERG responses and high myopia.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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