Familial Exudative Vitreoretinopathy, EVR7

Background and History: 

This is a progressive hereditary retinal disorder that often results in severe vision loss.

Clinical Correlations: 

Clinical findings are generally limited to the eye, and more specifically to the retina with onset at any age.  The blood vessels of the retina are abnormally porous and leak fluid into the retina.  This often irritates the vitreous, the jelly-like fluid that fills the chamber in the back of the eye, causing scarring and contraction which in turn cause holes in the retina and leads to detachments.

Surgery on the retina may slow this process and reduce the loss of vision but often there is residual scarring and loss of the rods and cones.  This process is highly variable among patients and the ultimate outcome is unpredictable even following retinal surgery.  Some eyes end up blind whereas others retain good functional vision.  There is no known treatment beyond surgery on the retina in an attempt to maintain good function.

Genetics: 

There are several types of FEVR and inheritance patterns vary.  For EVR7 discussed here the transmission pattern is vertical as affected parents' children have a 50% risk of inheriting this autosomal dominant disorder.  A specific mutation (change in DNA) is responsible. 

Diagnosis and Prognosis: 

This condition may be diagnosed at any age with a full eye examination by an ophthalmologist, usually when patients are aware of reduced vision in one or both eyes.  In very young children changes in behavior (such as bumping into things) may be the presenting sign.  A retinal specialist is important in the diagnosis and treatment.

There are no consistent abnormalities in the rest of the body and longevity is not impacted.  Low vision aids and mobility devices can also be helpful. 

Additional Information
Inheritance/Pedigree: 
Autosomal dominant