Persistent Hyperplastic Primary Vitreous

Clinical Characteristics
Ocular Features: 

Persistence and hyperplasia of the embryonic vitreous in most individuals results in significant ocular morbidity.  It results from a transcription factor deficiency in retinal ganglion cells which in turn negatively impacts development of the retinal vasculature.  As a consequence, the fetal hyaloid vasculature fails to regress and its persistence leads to a retrolental mass.

PHPV usually occurs unilaterally and affected eyes are generally blind from birth. Leukocoria secondary to the presence of a retrolental fibrovascular stalk is easily visible.  Nystagmus is frequently present and some patients have microphthalmos. The anterior segment may also be involved as evidenced by the presence of peripheral anterior synechiae, corneal opacities, cataracts, and glaucoma.  Contracture of the retrolental tissue In the posterior chamber results in the ciliary processes being pulled centrally and can lead to hemorrhage and retinal detachment. 

The clinical manifestations can make it difficult to distinguish from Norrie disease.

Systemic Features: 

No consistent systemic signs have been reported in PHPV individuals.

Genetics

The majority of PHPV cases occur sporadically, but families with transmission patterns compatible with both autosomal recessive and autosomal dominant patterns have been reported.

A six-generation family has been reported in which affected members had homozygous mutations in ATOH7 (10q21.3).  Based on mouse studies, this gene is expressed in the developing optic cup at the time that coincides with retinal ganglion cell formation.  Mice with absence of functioning Atoh7 lack retinal ganglion cells and optic nerves and develop PHPV.

A single family with presumed bilateral PHPV in 3 generations in a pattern consistent with autosomal dominant inheritance has been reported (611308).  However, no genotyping was reported and only the proband and his father had ophthalmologic examinations.

Treatment
Treatment Options: 

No medical or surgical treatment is effective.  The majority of individuals have no light perception.

References
Article Title: 

References

Prasov L, Masud T, Khaliq S, Mehdi SQ, Abid A, Oliver ER, Silva ED, Lewanda A, Brodsky MC, Borchert M, Kelberman D, Snowden JC, Dattani MT, Glaser T. ATOH7 mutations cause autosomal recessive persistent hyperplasia of the primary vitreous. Hum Mol Genet. 2012 May 29. [Epub ahead of print]

PubMedID: 22645276

Khaliq S, Hameed A, Ismail M, Anwar K, Leroy B, Payne AM, Bhattacharya SS, Mehdi SQ. Locus for autosomal recessive nonsyndromic persistent hyperplastic primary vitreous. Invest Ophthalmol Vis Sci. 2001 Sep;42(10):2225-8.

PubMedID: 11527934

Galal AH, Kotoury AI, Azzab AA. Bilateral persistent hyperplastic primary vitreous: an Egyptian family supporting a rare autosomal dominant inheritance. Genet Couns. 2006;17(4):441-7.

PubMedID: 17375531