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). Anterior segment dysgenesis is sometimes divided into subtypes including aniridia (see 106210), Axenfeld and Rieger anomalies, iridogoniodysgenesis, Peters anomaly, and posterior embryotoxon (Gould and John, 2002). Patients with ASGD6 have been reported with the Peters anomaly subtype. Peters anomaly consists of corneal opacity, defects in the posterior structures of the cornea, and iridocorneal and/or keratolenticular adhesions. Over 50% of patients develop glaucoma in childhood (summary by Vincent et al., 2001). [from OMIM]

Any mitochondrial DNA depletion syndrome in which the cause of the disease is a mutation in the OPA1 gene. [from MONDO]

Any early-onset non-syndromic cataract in which the cause of the disease is a mutation in the NHS gene. [from MONDO]

A rare genetic haematologic disease characterised by decreased or undetectable serum L-ferritin with otherwise normal laboratory parameters. Clinical signs and symptoms include generalised seizures, atypical restless leg syndrome, mild neuropsychologic impairment and progressive hair loss. Asymptomatic cases have also been reported. [from SNOMEDCT_US]

Foveal hypoplasia is defined as the lack of foveal depression with continuity of all neurosensory retinal layers in the presumed foveal area. Foveal hypoplasia as an isolated entity is a rare phenomenon; it is usually described in association with other ocular disorders, such as aniridia (106210), microphthalmia (see 251600), albinism (see 203100), or achromatopsia (see 216900). All reported cases of foveal hypoplasia have been accompanied by decreased visual acuity and nystagmus (summary by Perez et al., 2014). Genetic Heterogeneity of Foveal Hypoplasia Foveal hypoplasia-2 (FVH2; 609218) is caused by mutation in the SLC38A8 gene (615585) on chromosome 16q23. [from OMIM]

Axenfeld-Rieger syndrome is an autosomal dominant disorder of morphogenesis that results in abnormal development of the anterior segment of the eye, and results in blindness from glaucoma in approximately 50% of affected individuals (Fitch and Kaback, 1978). Systemic anomalies are associated, including dental hypoplasia, failure of involution of periumbilical skin, and maxillary hypoplasia (Alkemade, 1969). Genetic Heterogeneity of Axenfeld-Rieger Syndrome Linkage studies indicate that a second type of Axenfeld-Rieger syndrome maps to chromosome 13q14 (RIEG2; 601499). A third form of Axenfeld-Rieger syndrome (RIEG3; 602482) is caused by mutation in the FOXC1 gene (601090) on chromosome 6p25. See 109120 for a form of Axenfeld-Rieger syndrome associated with partially absent eye muscles, hydrocephalus, and skeletal abnormalities. [from OMIM]

PAX6-related aniridia occurs either as an isolated ocular abnormality or as part of the Wilms tumor-aniridia-genital anomalies-retardation (WAGR) syndrome. Aniridia is a pan ocular disorder affecting the cornea, iris, intraocular pressure (resulting in glaucoma), lens (cataract and lens subluxation), fovea (foveal hypoplasia), and optic nerve (optic nerve coloboma and hypoplasia). Individuals with aniridia characteristically show nystagmus and impaired visual acuity (usually 20/100 - 20/200); however, milder forms of aniridia with subtle iris architecture changes, good vision, and normal foveal structure do occur. Other ocular involvement may include strabismus and occasionally microphthalmia. Although the severity of aniridia can vary between and within families, little variability is usually observed in the two eyes of an affected individual. WAGR syndrome. The risk for Wilms tumor is 42.5%-77%; of those who develop Wilms tumor, 90% do so by age four years and 98% by age seven years. Genital anomalies in males can include cryptorchidism and hypospadias (sometimes resulting in ambiguous genitalia), urethral strictures, ureteric abnormalities, and gonadoblastoma. While females typically have normal external genitalia, they may have uterine abnormalities and streak ovaries. Intellectual disability (defined as IQ <74) is observed in 70%; behavioral abnormalities include attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, anxiety, depression, and obsessive-compulsive disorder. Other individuals with WAGR syndrome can have normal intellect without behavioral problems. [from GeneReviews]

Syndromic optic atrophy, also known as DOA+ syndrome, is a neurologic disorder characterized most commonly by an insidious onset of visual loss and sensorineural hearing loss in childhood with variable presentation of other clinical manifestations including progressive external ophthalmoplegia (PEO), muscle cramps, hyperreflexia, and ataxia. There appears to be a wide range of intermediate phenotypes (Yu-Wai-Man et al., 2010). [from OMIM]

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]

Axenfeld-Rieger syndrome is primarily an eye disorder, although it can also affect other parts of the body. This condition is characterized by abnormalities of the front part of the eye, an area known as the anterior segment. For example, the colored part of the eye (the iris), may be thin or poorly developed. The iris normally has a single central hole, called the pupil, through which light enters the eye. People with Axenfeld-Rieger syndrome often have a pupil that is off-center (corectopia) or extra holes in the iris that can look like multiple pupils (polycoria). This condition can also cause abnormalities of the cornea, which is the clear front covering of the eye.\n\nAbout half of affected individuals develop glaucoma, a serious condition that increases pressure inside the eye. When glaucoma occurs with Axenfeld-Rieger syndrome, it most often develops in late childhood or adolescence, although it can occur as early as infancy. Glaucoma can cause vision loss or blindness.\n\nThe signs and symptoms of Axenfeld-Rieger syndrome can also affect other parts of the body. Many affected individuals have distinctive facial features such as widely spaced eyes (hypertelorism); a flattened mid-face with a broad, flat nasal bridge; and a prominent forehead. The condition is also associated with dental abnormalities including unusually small teeth (microdontia) or fewer than normal teeth (oligodontia). Some people with Axenfeld-Rieger syndrome have extra folds of skin around their belly button (redundant periumbilical skin). Other, less common features can include heart defects, the opening of the urethra on the underside of the penis (hypospadias), narrowing of the anus (anal stenosis), and abnormalities of the pituitary gland that can result in slow growth.\n\nResearchers have described at least three types of Axenfeld-Rieger syndrome. The types, which are numbered 1 through 3, are distinguished by their genetic cause. [from MedlinePlus Genetics]

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. [from GeneReviews]

Neuroferritinopathy is an adult-onset progressive movement disorder characterized by chorea or dystonia and speech and swallowing deficits. The movement disorder typically affects one or two limbs and progresses to become more generalized within 20 years of disease onset. When present, asymmetry in the movement abnormalities remains throughout the course of the disorder. Most individuals develop a characteristic orofacial action-specific dystonia related to speech that leads to dysarthrophonia. Frontalis overactivity and orolingual dyskinesia are common. Cognitive deficits and behavioral issues become major problems with time. [from GeneReviews]

Any nanophthalmia in which the cause of the disease is a mutation in the MFRP gene. [from MONDO]

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). Anterior segment dysgenesis is sometimes divided into subtypes including aniridia (see 106210), Axenfeld and Rieger anomalies, iridogoniodysgenesis, Peters anomaly, and posterior embryotoxon (Gould and John, 2002). Some patients with ASGD3 have been reported with the following subtypes: iridogoniodysgenesis, Peters anomaly, Axenfeld anomaly, and Rieger anomaly. Iridogoniodysgenesis, which is characterized by iris hypoplasia, goniodysgenesis, and juvenile glaucoma, is the result of aberrant migration or terminal induction of the neural crest cells involved in the formation of the anterior segment of the eye (summary by Mears et al., 1996). Peters anomaly consists of a central corneal leukoma, absence of the posterior corneal stroma and Descemet membrane, and a variable degree of iris and lenticular attachments to the central aspect of the posterior cornea (Peters, 1906). In Axenfeld anomaly, strands of iris tissue attach to the Schwalbe line; in Rieger anomaly, in addition to the attachment of iris tissue to the Schwalbe line, there is clinically evident iris stromal atrophy with hole or pseudo-hole formation and corectopia (summary by Smith and Traboulsi, 2012). [from OMIM]

Groenouw type I, or granular type I, corneal dystrophy (CDGG1) is an autosomal dominant disorder characterized by irregular aggregates of hyaline material in the corneal stroma. These aggregates can cause significant visual disturbance and may require corneal transplantation for restoration of visual acuity or for relief from recurrent corneal erosions (summary by Stone et al., 1994). [from OMIM]

In most people with glaucoma, the damage to the optic nerves is caused by increased pressure within the eyes (intraocular pressure). Intraocular pressure depends on a balance between fluid entering and leaving the eyes.\n\nUsually glaucoma develops in older adults, in whom the risk of developing the disorder may be affected by a variety of medical conditions including high blood pressure (hypertension) and diabetes mellitus, as well as family history. The risk of early-onset glaucoma depends mainly on heredity.\n\nStructural abnormalities that impede fluid drainage in the eye increase ocular pressure. These abnormalities may be present at birth and usually become apparent during the first year of life. Such structural abnormalities may be part of a genetic disorder that affects many body systems, called a syndrome. If glaucoma appears before the age of 3 without other associated abnormalities, it is called primary congenital glaucoma.\n\nGlaucoma is a group of eye disorders in which the optic nerves connecting the eyes and the brain are progressively damaged. This damage can lead to reduction in side (peripheral) vision and eventual blindness. Other signs and symptoms may include bulging eyes, excessive tearing, and abnormal sensitivity to light (photophobia). The term "early-onset glaucoma" may be used when the disorder appears before the age of 40.\n\nOther individuals experience early onset of primary open-angle glaucoma, the most common adult form of glaucoma. If primary open-angle glaucoma develops during childhood or early adulthood, it is called juvenile open-angle glaucoma. [from MedlinePlus Genetics]

Lattice corneal dystrophy type IIIA (CDL3A) is an autosomal dominant condition characterized by amyloid accumulation in the corneal stroma. It is clinically manifest as the presence of thick ropy lattice lines in the cornea. Recurrent erosions are common. Onset occurs between 70 and 90 years of age (Yamamoto et al., 1998). [from OMIM]

Keratitis is a rare ocular disorder presenting with congenital and progressive features predominantly involving the anterior segment of the eye. The major clinical symptoms are anterior stromal corneal opacification and vascularization of the peripheral cornea. Progression of the opacification and vascularization into the central cornea may occur with corresponding reduction in visual acuity. Other anterior segment features include variable radial defects of the iris stroma and foveal hypoplasia (summary by Mirzayans et al., 1995). [from OMIM]

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. [from GeneReviews]