Familial Exudative Vitreoretinopathy, EVR5

Background and History: 

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.  EVR5 is one of several disorders that result from this process.

Clinical Correlations: 

There is considerable variation in the eye findings.  The abnormal blood vessel development in the retina may result in blindness among newborns but other patients can have only minor abnormalities into adulthood.  However, the vitreous humor (the gel-like material that fills the back part of the eye) abnormalities may progress leading to a pulling on the retina and eventually detaches it.  This is a threat throughout life.  A few individuals have cataracts and malformations in the cornea (the windshield of the eye) and iris (the colored part of the eye) with displaced pupils.

No general abnormalities outside the eye have been reported.


This condition results from mutations in a specific gene.  The inheritance pattern is somewhat variable.  Some family transmission patterns are consistent with an autosomal dominant inheritance mode in which affected parents have affected offspring.  In this case the risk of transmission from parent to child is 50%.  Only a single mutation is necessary.

Other individuals, usually more severely affected, have two copies of the mutation which is more consistent with an autosomal recessive condition.  In this case the clinically normal carrier parents each contribute a single copy of the mutation and each of their children have 25% risk of inheriting both copies and therefore having severe FEVR5.

Diagnosis and Prognosis: 

An ophthalmologist (eye doctor) can make the diagnosis at any age depending upon the stage of disease.  Longevity is not impacted but vision is highly variable, ranging from blindness to minimal impairment.  Lifelong monitoring is important as this is a progressive disease.  Patients with milder vision problems may benefit from low vision aids.

Additional Information
Autosomal dominant
Autosomal recessive