Syndrome with the unusual combination of spinocerebellar degeneration and corneal dystrophy. Three sisters born to normal consanguineous parents have been reported, one of who had only minor spinocerebellar signs without ocular involvement. This autosomal recessive syndrome differs from the Mousa-Al-Din-Al-Nassar syndrome by the subnormal intellectual development and the epithelial (versus stromal) nature of the corneal dystrophy.

Fuchs endothelial corneal dystrophy (FECD) is a progressive, bilateral condition characterized by dysfunction of the corneal epithelium, leading to reduced vision. The prevalence of FECD has been estimated at about 5% among persons over the age of 40 years in the United States. The vision loss in patients with FECD results from a loss of corneal transparency associated with irregularity of inner corneal layers in early disease and edema of the cornea in advanced disease. Ultrastructural features of FECD include loss and attenuation of endothelial cells, with thickening and excrescences of the underlying basement membrane. These excrescences, called guttae, are the clinical hallmark of FECD and become more numerous with progression of the disease. As the endothelial layer develops confluent guttae in the central cornea, the cells are no longer able to keep the cornea dehydrated and clear (summary by Baratz et al., 2010). Genetic Heterogeneity of Fuchs Endothelial Corneal Dystrophy More common, late-onset forms of FECD have been shown to be caused by mutation in the SLC4A11 gene (610206) on chromosome 20p13 (FECD4; 613268), in the ZEB1 gene (189909) on chromosome 10p11.2 (FECD6; 613270), and in the AGBL1 gene (615496) on chromosome 15q25 (FECD8; 615523). Other loci for late-onset FECD have been identified on chromosomes 13pter-q12.13 (FECD2; 610158), 18q21.2-q21.32 (FECD3; 613267), 5q33.1-q35.2 (FECD5; 613269), and 9p (FECD7; 613271).

Penttinen syndrome (PENTT) is characterized by a prematurely aged appearance involving lipoatrophy and epidermal and dermal atrophy, as well as hypertrophic lesions that resemble scars, thin hair, proptosis, underdeveloped cheekbones, and marked acroosteolysis (Johnston et al., 2015).

Fuchs endothelial corneal dystrophy (FECD) is the most common genetic disorder of the corneal endothelium. Late-onset FECD is marked by thickening of Descemets membrane and excrescences, called guttae, that typically appear in the fourth or fifth decade. Disease progression results in decreased visual acuity as a result of increasing corneal edema, and end-stage disease is marked by painful epithelial bullae (summary by Riazuddin et al., 2013). Patients with keratoconus have been observed (Lechner et al., 2013). For a discussion of genetic heterogeneity of Fuchs endothelial corneal dystrophy, see FECD1 (136800).

Late-onset Fuchs endothelial corneal dystrophy (FECD) is a degenerative disorder affecting roughly 4% of the population older than 40 years. It is distinguished from other corneal disorders by the progressive formation of guttae, which are microscopic refractile excrescences of the Descemet membrane, a collagen-rich basal lamina secreted by the corneal endothelium. From onset, it usually takes 2 decades for FECD to impair endothelial cell function seriously, leading to stromal edema and impaired vision (Sundin et al., 2006). For a discussion of genetic heterogeneity of Fuchs endothelial corneal dystrophy, see FECD1 (136800).

Anterior segment dysgeneses (ASGD or ASMD) are a heterogeneous group of developmental disorders affecting the anterior segment of the eye, including the cornea, iris, lens, trabecular meshwork, and Schlemm canal. The clinical features of ASGD include iris hypoplasia, an enlarged or reduced corneal diameter, corneal vascularization and opacity, posterior embryotoxon, corectopia, polycoria, an abnormal iridocorneal angle, ectopia lentis, and anterior synechiae between the iris and posterior corneal surface (summary by Cheong et al., 2016).

Primary congenital glaucoma (PCG) is characterized by elevated intraocular pressure (IOP), enlargement of the globe (buphthalmos), edema, and opacification of the cornea with rupture of Descemet's membrane (Haab's striae), thinning of the anterior sclera and iris atrophy, anomalously deep anterior chamber, and structurally normal posterior segment except for progressive glaucomatous optic atrophy. Symptoms include photophobia, blepharospasm, and excessive tearing. Typically, the diagnosis is made in the first year of life. Depending on when treatment is instituted, visual acuity may be reduced and/or visual fields may be restricted. In untreated individuals, blindness invariably occurs.