First Author: T.Hirakata JAPAN
Co Author(s): T. Negishi A. Murakami
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Oguchi disease is a recessively inherited stationary night blindness. However, a few cases of progressive cone dysfunction in Oguchi disease are also reported. We have observed a Japanese patient with Oguchi disease for more than 9 years who was finally revealed as a progressive cone dysfunction with SAG gene mutation. And we also report the possibilities of image analysis taken by adaptive optics (AO).
The patient was observed in Department of Ophthalmology, Juntendo University School of Medicine and Department of Ophthalmology, Saitama Children’s Medical centre.
A full medical history was obtained and genetic analysis was performed for patient and his parents. Comprehensive ophthalmologic examinations were performed, including visual acuity (VA), ophthalmoscopy, autofluorescence (AF) imaging, optical coherence tomography (OCT), visual field test by Goldman perimetry (GP), adaptometer, electrophysiological assessments (full-field ERG; ffERG and multi focal ERG; mfERG) that incorporated the ISCEV standards. Additionally, AO was performed in the macular.
A Japanese boy was pointed out about low VA in a school medical examination at the age of 6. Corrected vision was (1.2) in each eye at that time, while ophthalmoscopy showed golden-yellow discolouration of the fundus that disappeared in the long dark-adapted state (Mizuo-Nakamura phenomenon). Adaptometer revealed scotopic response was diminished. Dark adapted dim flash ERG showed non-recordable and bright flash ERG had electronegative configuration. Light adapted test was normal at the age of 6. Genetic analysis found the mutation of A 1-bp deletion (1147delA) in the SAG (also known as arrestin or S-antigen) gene; the patient had a homozygous, and each parent had a heterozygous mutation. Thus, he was diagnosed as Oguchi disease, inherited stationary night blindness. At the age of 15, he noticed night blindness changed worse, so electrophysiological examinations were performed again. Dark adapted ERG showed as same as at the age of 6. However, light adapted cone ERG was moderately affected in both eyes. OCT showed disappeared outer retinal layer including EZ and IZ line in the peripheral macular in both eyes. AO showed decreased cone cells compared with normal control in the macular.
Cone dysfunction in Oguchi disease with 1147delA in the SAG gene was documented. Although an 1147delA in the SAG gene is the most frequently seen mutation in Japanese Oguchi disease patients who shows stationary night blindness, our patient showed progressive history. AO images might reflect the survival of cone photoreceptor cells more in more detail than OCT images.