Cataracts, Congenital with Sclerocornea and Glaucoma

Clinical Characteristics
Ocular Features: 

The ocular features are evident at birth or within the first year of life and may be asymmetrical.  The phenotype is heterogeneous but does not appear to be progressive.  The anterior chambers are of normal depth and the fundi are normal when visualization is possible.  The corneal opacification is usually denser peripherally and resembles corneoscleralization but it can extend centrally to a variable degree.  In individuals with glaucoma and buphthalmos the cornea is more opaque and usually vascularized. In such eyes the cornea is thinned.  In most patients the corneal diameters were 5-8 mm in diameter but in those with elevated pressures the anterior segment was obviously buphthalmic. Iridocorneal adhesions may be present.  The lenses are cataractous but the capsules are normal.  Microphthalmia has been reported in some patients.  Vision is often in the range of hand motions.    

Systemic Features: 

None.

Genetics

Homozygous mutations in PXDN (2p25.3) encoding peroxidasin are believed responsible for this autosomal recessive condition.  Mammalian peroxidasin localizes to the endoplasmic reticulum but is also found in the extracellular matrix and is believed important to the maintainence of basement membrane integrity.  The protein is one of several that aids in the extracellular breakdown of hydrogen peroxide and free radicals.  In mouse eyes it localizes to the corneal and lens epithelium but its role in maintaining transparency of the lens and cornea is unknown.

See also Cataracts, Congenital Zonular Pulverulent 1 (116200) in this database for a condition with a similar phenotype but caused by heterozygous mutations in the GJA8 gene.

Treatment
Treatment Options: 

No information regarding treatment is available but cataract and corneal surgery may be beneficial.   

References
Article Title: 

Novel mutations in PXDN cause microphthalmia and anterior segment dysgenesis

Choi A, Lao R, Ling-Fung Tang P, Wan E, Mayer W, Bardakjian T, Shaw GM, Kwok PY, Schneider A, Slavotinek A. Novel mutations in PXDN cause microphthalmia and anterior segment dysgenesis. Eur J Hum Genet. 2014 Jun 18. doi: 10.1038/ejhg.2014.119. [Epub ahead of print] PubMed PMID: 24939590.

PubMed ID: 
24939590

Homozygous mutations in PXDN cause congenital cataract, corneal opacity, and developmental glaucoma

Khan K, Rudkin A, Parry DA, Burdon KP, McKibbin M, Logan CV, Abdelhamed ZI, Muecke JS, Fernandez-Fuentes N, Laurie KJ, Shires M, Fogarty R, Carr IM, Poulter JA, Morgan JE, Mohamed MD, Jafri H, Raashid Y, Meng N, Piseth H, Toomes C, Casson RJ, Taylor GR, Hammerton M, Sheridan E, Johnson CA, Inglehearn CF, Craig JE, Ali M. Homozygous mutations in PXDN cause congenital cataract, corneal opacity, and developmental glaucoma. Am J Hum Genet. 2011 Sep 9;89(3):464-73.

PubMed ID: 
21907015

References

Choi A, Lao R, Ling-Fung Tang P, Wan E, Mayer W, Bardakjian T, Shaw GM, Kwok PY, Schneider A, Slavotinek A. Novel mutations in PXDN cause microphthalmia and anterior segment dysgenesis. Eur J Hum Genet. 2014 Jun 18. doi: 10.1038/ejhg.2014.119. [Epub ahead of print] PubMed PMID: 24939590.

PubMedID: 24939590

Khan K, Rudkin A, Parry DA, Burdon KP, McKibbin M, Logan CV, Abdelhamed ZI, Muecke JS, Fernandez-Fuentes N, Laurie KJ, Shires M, Fogarty R, Carr IM, Poulter JA, Morgan JE, Mohamed MD, Jafri H, Raashid Y, Meng N, Piseth H, Toomes C, Casson RJ, Taylor GR, Hammerton M, Sheridan E, Johnson CA, Inglehearn CF, Craig JE, Ali M. Homozygous mutations in PXDN cause congenital cataract, corneal opacity, and developmental glaucoma. Am J Hum Genet. 2011 Sep 9;89(3):464-73.

PubMedID: 21907015