Stargardt's disease

Stargardt disease (yellow spotted fundus, yellow spotted dystrophy) is a dystrophy of the macular region of the retina, which begins in the pigment epithelium and is manifested by a bilateral decrease in visual acuity at the age of 10-20 years.

Stargardt's disease was described by K. Stargardt at the beginning of the 20th century as a hereditary disease of the macular region with a polymorphic ophthalmoscopic picture: "bronzed bronze", "bull's eye", choroidal atrophy, etc.

By positional cloning, the main gene locus for Stargardt disease expressed in photoreceptors was determined and was named ABCR. In the autosomal dominant type of inheritance of Stargardt disease, the localization of mutated genes was established in chromosomes 13q and 6ql4.

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Symptoms and diagnosis of Stargardt disease

Results of genetic studies conducted in recent years indicate that, despite differences in clinical presentation, retinitis pigmentosa, Stargardt disease, yellow spotted fundus, and age-related macular degeneration are allelic disorders of the ABCR locus.

The bull's-eye phenomenon is ophthalmoscopically visible as a dark center surrounded by a broad ring of hypopigmentation, usually followed by a ring of hyperpigmentation. On FAG, in typical bull's-eye, areas of no fluorescence or hypofluorescence with visible choriocapillaries are revealed against a normal background. Histologically, an increase in the amount of pigment in the central zone of the fundus, atrophy of the adjacent retinal pigment epithelium, and a combination of atrophy and hypertrophy of the pigment epithelium are noted. The absence of fluorescence in the macular region is explained by the accumulation of lipofuscin in the retinal pigment epithelium, which acts as a screen for fluorescein. Lipofuscin, in addition, weakens the oxidative function of lysosomes and increases the pH of retinal pigment epithelium cells, which leads to the loss of their membrane integrity.

There is a rare form of yellow-spot dystrophy without changes in the macular area. In this case, multiple yellowish spots of various shapes are visible between the macula and the equator: round, oval, elongated, which can merge or be located separately from each other. Over time, the color, shape and size of these spots can change; the picture on the FAG also changes: areas with hyperfluorescence become hypofluorescent, which corresponds to atrophy of the retinal pigment epithelium.

All patients with Stargardt disease have relative or absolute central scotomas of varying sizes depending on the spread of the process. In yellow spot dystrophy, the visual field may be normal in the absence of changes in the macular region.

Most patients experience changes in color vision such as deuteranopia, red-green dyschromasia, or more pronounced ones. In yellow spot dystrophy, color vision may be normal.

Spatial contrast sensitivity in Stargardt dystrophy is significantly altered in the entire frequency range with a significant decrease in the middle frequency range and its complete absence in the high spatial frequency range - the "cone dystrophy pattern". Contrast sensitivity is absent in the central region of the retina within 6-10°.

In the initial stages of Stargardt's dystrophy and yellow spot dystrophy, ERG and EOG remain within normal limits; in advanced stages, cone components of ERG decrease and EOG indices become subnormal. Local ERG is subnormal already in the early stages of the disease and becomes unrecordable as the disease progresses.

Differential diagnosis of Stargardt disease should be carried out with dominant progressive foveal dystrophy, cone, cone-rod and rod-cone dystrophy, juvenile retinoschisis, vitelliform macular dystrophy, acquired drug-induced dystrophies (for example, with chloroquine retinopathy), and severe toxicosis of pregnancy.

Treatment of Stargardt's disease

There is no pathogenetically proven treatment. Wearing sunglasses is recommended to prevent the damaging effects of light.