Oguchi Disease, Type 1

Clinical Characteristics
Ocular Features: 

The distinctive feature of Oguchi disease is the peculiar and distinctive discoloration of the fundus under various light conditions, known as the Mizuo phenomenon.  Typically, the fundus assumes a golden or gray-white coloration under light adapted conditions but this disappears during acute dark adaptation and only reappears after prolonged time spent in darkness.  Rod dark adaptation is markedly delayed while that of cones is normal.  Visual acuity, visual fields and color vision are all normal.   A- and b-waves on single flash ERG are decreased or absent under lighted conditions but increase after prolonged dark adaptation.  Night blindness is present from birth without progression.

Systemic Features: 

No systemic abnormalities are associated with Oguchi disease.

Genetics

Oguchi type 1 disease is an autosomal recessive condition caused by mutations in the arrestin (SAG) gene (2q37.1) whose product is an intrinsic photoreceptor protein that participates in the recovery phase of light transduction.

Oguchi disease type 2 (613411), a similar form of congenital stationary night blindness, is caused by mutations in the GRK1 gene.  Genotyping is required to distinguish between the two types.

Treatment
Treatment Options: 

No treatment is available.

References
Article Title: 

References

Fuchs S, Nakazawa M, Maw M, Tamai M, Oguchi Y, Gal A. A homozygous 1-base pair deletion in the arrestin gene is a frequent cause of Oguchi disease in Japanese. Nat Genet. 1995 Jul;10(3):360-2.

PubMedID: 7670478

Maw MA, John S, Jablonka S, M?oller B, Kumaramanickavel G, Oehlmann R, Denton MJ, Gal A. Oguchi disease: suggestion of linkage to markers on chromosome 2q. J Med Genet. 1995 May;32(5):396-8.

PubMedID: 7616550