Familial Exudative Vitreoretinopathy, EVR2

Clinical Characteristics
Ocular Features: 

The basis for many of the ocular complications likely begins with incomplete development of the retinal vasculature.  Resulting retinal ischemia leads to neovascularization, vitreous hemorrhage and traction, and retinal folds, with some 20% going on to develop rhegmatogenous or traction detachments.  There is, however, considerable clinical variability, even within families, with some infants blind from birth whereas some (41%) adults have only areas of remaining avascularity or evidence of macular dragging.  In fact, some affected individuals are asymptomatic and diagnosed only as part of extensive family studies.  Intraretinal lipid is often seen.  Considerable asymmetry in the two eyes is common.  Secondary cataracts often occur and phthisis bulbi results in some patients.  The clinical picture is sometimes confused with retinopathy of prematurity.

Systemic Features: 

No consistent systemic abnormalities have been identified in EVR2.

Genetics

Familial exudative vitreoretinopathy is the name given to a clinically and genetically heterogeneous group of disorders caused by mutations in several genes.  Autosomal dominant (e.g., EVR1; 133780), and X-linked inheritance (this condition) have been reported with the former much more common. 

The X-linked form of FEVR (EVR2 described here) results from mutations in the NDP gene (Xp11.3) and is allelic to Norrie disease (310600).

Retinopathy of prematurity can be called a phenocopy of FEVR.

Treatment
Treatment Options: 

Retinal, vitreal, and cataract surgery are indicated in appropriate cases.

References
Article Title: 

References

Kondo, H., Qin, M., Kusaka, S., Tahira, T., Hasebe, H., Hayashi, H., Uchio, E., Hayashi, K. Novel mutations in Norrie disease gene in Japanese patients with Norrie disease and familial exudative vitreoretinopathy. Invest. Ophthal. Vis. Sci. 48: 1276-1282, 2007.

PubMedID: 17325173

Chen, Z.-Y., Battinelli, E. M., Fielder, A., Bundey, S., Sims, K., Breakefield, X. O., Craig, I. W. A mutation in the Norrie disease gene (NDP) associated with X-linked familial exudative vitreoretinopathy. Nature Genet. 5: 180-183, 1993.

PubMedID: 8252044