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From perfect visual function to ‘legally’ blind in one year: new mutations in progressive cone dystrophy
Author(s) -
Sousa Neves F.,
Braga J.,
Loureiro M.,
Arede C.,
Sequeira J.,
Varandas R.
Publication year - 2016
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2016.0589
Subject(s) - abca4 , electroretinography , ophthalmology , medicine , dystrophy , visual acuity , retinal pigment epithelium , fundus (uterus) , erg , maculopathy , stargardt disease , posterior pole , proband , retinal , retinopathy , pathology , mutation , biology , genetics , diabetes mellitus , endocrinology , gene , phenotype
Purpose We aim to report a case of a 15 year‐old patient with severe and rapid bilateral visual impairment due to progressive cone dystrophy and describe the associated mutations. Methods This is a case report of a patient with a rare disease who underwent full ophthalmologic evaluations including optical coherence tomography (OCT) of the posterior pole, fundus autofluorescence (FAF) and electroretinography (ERG). Results A 15‐year‐old girl was presented at our Department with progressive vision loss and poor colour vision complaints. The patient reported these complaints for a year, despite a full uneventful ophthalmic evaluation at that time. Best‐corrected visual acuity was 6/60 for each eye and Ishihara 24‐plates colour test was altered. Fundoscopic evaluation showed a maculopathy with spotty pigment changes in addition to temporal pallor of the optic disk. Posterior pole OCT showed a reduced outer nuclear layer and retinal pigment epithelium unspecific changes. FAF revealed a central dark area surrounded by a ring of increased autofluorescence. ERG was inconclusive due to poor collaboration, although it was hypothesised to have a slight cone dysfunction. Moreover, genetic analyses of ABCA4 and CDHR1 genes were found to be positive for multiple mutations. The c.6816 + 2T>A (p.Leu2035Pro) mutation was never described and the c.6104T>C (p.Leu2035Pro) mutation was only present in one patient with Stargardt disease. After a period of 2 years of follow‐up visual function and retinal disease remained stable. Conclusions Progressive cone dystrophy is a rare inherited ocular disorder characterized by the loss of cone cells. This case report emphasizes the need to reach a clear diagnosis when uncommon symptoms appear in an otherwise normal ophthalmic evaluation and also describe newer mutations in ABCA4 gene enhancing our knowledge about this disease.