Familial Exudative Vitreoretinopathy, EVR6

Background and History: 

This is a recently described hereditary disorder of retinal vasculature and the vitreous (the usually clear jelly-like material that fills the eye).  Vitreoretinopathy refers to a condition in the back of the eye in which a primary retinal disease also impacts the vitreous, the jelly-like material that fills much of the eye.  It is believed to begin at birth when the retinal vessels are interrupted in development causing the retina to be starved of oxygen.  This sets into motion a chain of events that leads to the growth of new abnormal vessels which subsequently bleed causing scarring of the retina and vitreous that may ultimately cause a retinal detachment and blindness.  EVR6 is one of several disorders that result from this process.

Clinical Correlations: 

The onset of this disorder is during embryonic development but it may not be detected until much later when individuals complain of poor vision.   Detailed examination of the eye, especially the retina, may be required to detect the presence of abnormalities.  There is a wide range of clinical abnormalities with some patients having severe vision problems whereas others have normal to near normal vision.  Minor disease consisting of abnormal pigmentation of the retina and anomalies of retinal vessels can be the only evidence of this condition but in other patients the retina becomes detached leading to blindness.   Some but not all patients develop opacities in the lens called cataracts.  There are no signs and symptoms elsewhere in the body.

Genetics: 

A mutation (change) in a specific gene is responsible for this condition.  Affected parents can pass the abnormal gene directly to their children with a 50% probability.  It is sometimes called an autosomal dominant disorder since only one member of a gene pair needs to be mutated in order to develop this condition.

Diagnosis and Prognosis: 

There are usually no obvious signs at birth and the only way to detect disease is by a detailed examination of the eyes by an ophthalmologist.  A retinal specialist should be consulted. 

This is a progressive disorder and requires lifelong monitoring.  Certain eye features such as retinal detachments, internal bleeding, and cataracts can be treated surgically but no cure for the progression of disease is available.  The prognosis for vision is unpredictable and highly variable.

Additional Information
Inheritance/Pedigree: 
Autosomal dominant