MedGen

Pseudoxanthoma elasticum (PXE) is a systemic disorder that affects the elastic tissue of the skin, the eye, and vascular system. Individuals most commonly present with angioid streaks of the retina found on routine eye examination or associated with retinal hemorrhage and/or characteristic papules in the skin. The most frequent cause of morbidity and disability in PXE is reduced vision due to complications of subretinal neovascularizations and macular atrophy. Other manifestations include premature gastrointestinal angina and/or bleeding, intermittent claudication of arm and leg muscles, stroke, renovascular hypertension, and cardiovascular complications (angina/myocardial infarction). Most affected individuals live a normal life span. [from GeneReviews]

Leber congenital amaurosis, also known as LCA, is an eye disorder that is present from birth (congenital). This condition primarily affects the retina, which is the specialized tissue at the back of the eye that detects light and color. People with this disorder typically have severe visual impairment beginning at birth or shortly afterward. The visual impairment tends to be severe and may worsen over time.

A specific behavior called Franceschetti's oculo-digital sign is characteristic of Leber congenital amaurosis. This sign consists of affected individuals poking, pressing, and rubbing their eyes with a knuckle or finger. Poking their eyes often results in the sensation of flashes of light called phosphenes. Researchers suspect that this behavior may contribute to deep-set eyes in affected children.

Leber congenital amaurosis is also associated with other vision problems, including an increased sensitivity to light (photophobia), involuntary movements of the eyes (nystagmus), and extreme farsightedness (hyperopia). The pupils, which usually expand and contract in response to the amount of light entering the eye, do not react normally to light. Instead, they expand and contract more slowly than normal, or they may not respond to light at all.

At least 20 genetic types of Leber congenital amaurosis have been described. The types are distinguished by their genetic cause, patterns of vision loss, and related eye abnormalities.

In very rare cases, delayed development and intellectual disability have been reported in people with the features of Leber congenital amaurosis. Because of the visual loss, affected children may become isolated. Providing children with opportunities to play, hear, touch, understand and other early educational interventions may prevent developmental delays in children with Leber congenital amaurosis. [from MedlinePlus Genetics]

Any retinitis pigmentosa in which the cause of the disease is a mutation in the PRPF8 gene. [from MONDO]

Microphthalmia-retinitis pigmentosa-foveoschisis-optic disc drusen syndrome is a rare, genetic, non-syndromic developmental defect of the eye disorder characterized by the association of posterior microphthalmia, retinal dystrophy compatible with retinitis pigmentosa, localized foveal schisis and optic disc drusen. Patients present high hyperopia, usually adult-onset progressive nyctalopia and reduced visual acuity, and, on occasion, acute-angle glaucoma. [from ORDO]

Any retinitis pigmentosa in which the cause of the disease is a mutation in the IFT172 gene. [from MONDO]

Nanophthalmos is characterized by axial lengths of the ocular globe that are more than 2 SDs smaller than the normal range, or less than 20 mm in adults, with a cornea and lens that are typically of normal size, associated with severe hyperopia (farsightedness) of +7.00 diopters or more. The smaller dimensions of the anterior chamber depth cause the iridocorneal angle to be typically narrow. Abnormal thickening of the scleral connective tissue is often observed (summary by Awadalla et al., 2014). For a discussion of genetic heterogeneity of nanophthalmos, see NNO1 (600165). [from OMIM]

Optic disc drusen are acellular, calcified deposits within the optic nerve head. Optic disc drusen are congenital and developmental anomalies of the optic nerve head, representing hyaline-containing bodies that, over time, appear as elevated, lumpy irregularities on the anterior portion of the optic nerve. [from HPO]