USE OF SPECTRAL DOMAIN-OPTICAL COHERENCE TOMOGRAPHY TO VISUALIZE PHOTORECEPTOR ABNORMALITIES IN CONE-ROD DYSTROPHY 6

Abstract

The purpose of this study was to describe the spectral domain-optical coherence tomography findings in a patient with cone-rod dystrophy 6. This is a case report of a 13-year-old girl who presented with progressive loss of vision. Fundus photography, a fluorescein angiogram, an electroretinogram, autofluorescence imaging, spectral domain-optical coherence tomography, and genetic testing were performed. The patient's fundi showed mild granularity of the perifoveal retinal pigment epithelium. An electroretinogram showed cone dysfunction and normal rod function. Genetic testing showed a heterozygous CGC>CAC nucleotide substitution at codon 838 of the GUCY2D gene. This results in an amino acid change of Arg838His and provides a molecular diagnosis of cone-rod dystrophy 6. The spectral domain-optical coherence tomography showed abnormalities at the inner segment/outer segment junction and the outer segment layer suggestive of loss or disease of photoreceptor outer segments. Autofluorescence imaging showed a perifoveal ring of hyperfluorescence that correlated with abnormallities on spectral domain-optical coherence tomography. Spectral domain-optical coherence tomography can show photoreceptor abnormalities that correlate with the perifoveal ring seen with autofluorescence imaging of patients with cone-rod dystrophy 6. Spectral domain-optical coherence tomography has significant potential for understanding and following the natural history of diseases such as cone-rod dystrophy 6.