Best Disease

Inherited, gradually starting, progressive, polymorphic macular degeneration.

Vitelliform Macular Dystrophy; Polymorphic Vitelline Macular Degeneration; Juvenile Vitelliform Macular Dystrophy.

Unknown. Several large kindreds have been reported in the literature, with one gene source being traced back to the 17th century in Sweden.

Autosomal dominant inheritance. Gene linkage studies demonstrated the gene responsible for Best disease is located on chromosome 11q13. However, later work illustrated the genetic heterogeneity of the condition and described several allelic variants. One case of nonpenetrance of Best disease has been reported.

Characterized by a gross yellow or orange discoid subretinal lesion in the macula. Histopathologic findings on postmortem specimens showed excessive lipofuscin accumulation in the retinal pigment epithelial cells and the subretinal pigment epithelial cell space. The final stage of retinal pigment epithelial atrophy, uncommon before the age of 40 years, may result in a choroidal neovascularization membrane with further loss in visual acuity.

Usually diagnosed between 3 and 16 years of age, with a mean age at manifestation of 6 years. The diagnosis is based on the characteristic appearance of a discoid lesion in the macula, which usually is bilateral, but may be asymmetric. The mass described in the macular area initially has the appearance of the intact yolk of a fried egg and seems to be present at birth. Progression of the disease with abnormal pigmentation then results in a picture called scrambling the egg. Photoreceptor loss occurs in the affected area, and the origin of the accumulated material is thought to derive from degenerated pigment epithelial cells of the retina. Patients and carriers of the disorder have abnormal responses in the electrooculogram. Electroretinographic responses remain normal.

Fundoscopy reveals the changes usually before visual impairment exists. Therefore visual acuity usually is normal at first manifestation, but the condition tends to be progressive over many years and results in abnormal pigmentation, chorioretinal atrophy, and gradual visual impairment. No systemic manifestations of the condition have been noted. No effective treatment for this disease is known. Although rare, marked loss of central vision may render patients legally blind. Choroidal neovascularization can be controlled by laser treatment.

No specific precautions are required.

Especially in younger patients undergoing ophthalmic examination under general anesthesia, oculocardiac reflex with profound bradycardia should be expected. Treatment is twofold and includes first stopping the stimulation and second, if still necessary, anticholinergic drugs. No other specific precautions are required.

No known specific pharmacological implications.

Stargardt Syndrome: Inherited and rapidly progressive macular degeneration with juvenile onset.

Central Serous Retinopathy (Central Serous Chorioretinopathy): Retinal pigment epithelial disorder generally occurring in patients younger than 50 years and presenting with unilateral, acute decrease of visual acuity.