Sorsby pseudoinflammatory fundus dystrophy
Clinical characteristics
Ocular Features:
Sorsby Pseudoinflammatroy Fundus Dystrophy is characterized by progressive degeneration of the central macula of the retina with edema, hemorrhages and exudates with pigment changes. The onset is typically in the second to fourth decade with development of a disciform central macular atrophy with white and yellow spots (not drusen). This is followed by subretinal neovascular
membranes in the majority of patients. Further degeneration occurs over years and can spread from the center to the periphery of the retina with a corresponding visual field defect. Night blindness or difficulties adapting to changes in light intensity may be noted before the central macular degeneration occurs. In histopathologic studies, a subretinal deposit can be observed in Bruchs membrane.
Systemic Features:
No general systemic manifestations are associated with Sorsby Pseudoinflammatory Fundus Dystrophy.
Genetics
Sorsby Pseudoinflammatory Fundus Dystrophy is an autosomal dominant disorder, caused by mutations in the TIMP3 gene, located at 22q12.1-q13.2. Evidence for a separate recessive form (264420) is somewhat refuted by the fact that genotyping found heterozygosity of the TIMP3 mutation in some families.
Pedigree:
Autosomal dominant
Treatment
In patients with early stages of the disease, a daily dose of 50,000 IU Vitamin A given by mouth has been shown to reverse the symptoms of night blindness. Treatment with anti-angiogenic agents or steroids has shown improvement in visual acuity in some patients. Patients with decreased vision may find benefit with low vision aids.