Sturge-Weber syndrome is characterized by an intracranial vascular anomaly, leptomeningeal angiomatosis, most often involving the occipital and posterior parietal lobes. The most common symptoms and signs are facial cutaneous vascular malformations (port-wine stains), seizures, and glaucoma. Stasis results in ischemia underlying the leptomeningeal angiomatosis, leading to calcification and laminar cortical necrosis. The clinical course is highly variable and some children experience intractable seizures, mental retardation, and recurrent stroke-like episodes (review by Thomas-Sohl et al., 2004).

Classic Saethre-Chotzen syndrome (SCS) is characterized by coronal synostosis (unilateral or bilateral), facial asymmetry (particularly in individuals with unicoronal synostosis), strabismus, ptosis, and characteristic appearance of the ear (small pinna with a prominent superior and/or inferior crus). Syndactyly of digits two and three of the hand is variably present. Cognitive development is usually normal, although those with a large genomic deletion are at an increased risk for intellectual challenges. Less common manifestations of SCS include other skeletal findings (parietal foramina, vertebral segmentation defects, radioulnar synostosis, maxillary hypoplasia, ocular hypertelorism, hallux valgus, duplicated or curved distal hallux), hypertelorism, palatal anomalies, obstructive sleep apnea, increased intracranial pressure, short stature, and congenital heart malformations.

Norrie disease is an X-linked recessive disorder characterized by very early childhood blindness due to degenerative and proliferative changes of the neuroretina. Approximately 50% of patients show some form of progressive mental disorder, often with psychotic features, and about one-third of patients develop sensorineural deafness in the second decade. In addition, some patients have more complex phenotypes, including growth failure and seizures (Berger et al., 1992). Warburg (1966) noted confusion of the terms 'pseudoglioma' and microphthalmia with Norrie disease in the literature. 'Pseudoglioma' is a nonspecific term for any condition resembling retinoblastoma and can have diverse causes, including inflammation, hemorrhage, trauma, neoplasia, or congenital malformation, and often shows unilateral involvement. Thus, 'pseudoglioma' is not an acceptable clinical or pathologic diagnosis (Duke-Elder, 1958).

The primary characteristics of the Frank-ter Haar syndrome (FTHS) are brachycephaly, wide fontanels, prominent forehead, hypertelorism, prominent eyes, macrocornea with or without glaucoma, full cheeks, small chin, bowing of the long bones, and flexion deformity of the fingers. Protruding, simple ears and prominent coccyx are also regarded as important diagnostic signs (summary by Maas et al., 2004). Borrone syndrome was described as a severe progressive multisystem disorder with features overlapping those of FTHS, including thick skin, acne conglobata, osteolysis, gingival hypertrophy, brachydactyly, camptodactyly, and mitral valve prolapse. Although it was initially thought to be a distinct phenotype, mutations in the FTHS-associated gene SH3PXD2B have been identified in patients diagnosed with Borrone syndrome. The earlier differential description was attributed to phenotypic variability as well as to differences in the ages at which patients were examined (Wilson et al., 2014).

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.

Neonatal diabetes mellitus with congenital hypothyroidism (NDH) syndrome is characterized by intrauterine growth retardation and onset of nonimmune diabetes mellitus within the first few weeks of life. Other features include renal parenchymal disease, primarily renal cystic dysplasia, and hepatic disease, with hepatitis in some patients and hepatic fibrosis and cirrhosis in others. Facial dysmorphism, when present, consistently involves low-set ears, epicanthal folds, flat nasal bridge, long philtrum, and thin upper lip. Most patients exhibit developmental delay (Dimitri et al., 2015).

Persistent hyperplastic primary vitreous (PHPV), also termed 'persistent fetal vasculature,' is a developmental malformation of the eye in which the primary vitreous fails to regress in utero, resulting in the presence of a retrolental fibrovascular membrane with persistence of the posterior portion of the tunica vasculosa lentis and hyaloid artery. This abnormality is usually unilateral and associated with microphthalmia, cataract, glaucoma, and congenital retinal nonattachment (see Haddad et al., 1978; Khaliq et al., 2001; Prasov et al., 2012). PHPV shares phenotypic overlap with Norrie disease (310600). Genetic Heterogeneity of Persistent Hyperplastic Primary Vitreous A dominant form of PHPV has been described (PHPVAD; 611308).

Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A), which includes both the more severe Walker-Warburg syndrome (WWS) and the slightly less severe muscle-eye-brain disease (MEB), is an autosomal recessive disorder with characteristic brain and eye malformations, profound mental retardation, congenital muscular dystrophy, and death usually in the first years of life. It represents the most severe end of a phenotypic spectrum of similar disorders resulting from defective glycosylation of DAG1 (128239), collectively known as 'dystroglycanopathies' (van Reeuwijk et al., 2005). For a general phenotypic description and a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type A, see MDDGA1 (236670).

An autosomal recessive muscular dystrophy caused by mutations in the POMGNT1 gene. It is associated with characteristic brain and eye malformations, profound mental retardation, and death usually in the first years of life.

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). In sclerocornea there is congenital, nonprogressive corneal opacification that may be peripheral, sectoral, or central in location. Visual prognosis is related to the central corneal involvement. The cornea has a flat curvature. The majority of cases are bilateral (summary by Smith and Traboulsi, 2012). Isolated sclerocornea is caused by displacement of the limbal arcades and may be associated with cornea plana; in this condition, the anterior chamber is visible and the eye is not microphthalmic. In complex sclerocornea, however, corneal opacification is associated with microphthalmia, cataract, and/or infantile glaucoma. The central cornea is usually relatively clear, but the thickness is normal or increased, never reduced (summary by Nischal, 2007).

Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A) is an autosomal recessive disorder with characteristic brain and eye malformations, profound mental retardation, and congenital muscular dystrophy. The phenotype includes the alternative clinical designation Walker-Warburg syndrome (WWS), which is associated with death in infancy. The disorder represents the most severe end of a phenotypic spectrum of similar disorders resulting from defective glycosylation of alpha-dystroglycan (DAG1), collectively known as 'dystroglycanopathies' (summary by Geis et al., 2013 and Riemersma et al., 2015). For a general phenotypic description and a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type A, see MDDGA1 (236670).

A rare genetic eye disease with characteristics of optic disc anomalies (bilateral colobomatous optic discs, retinal vessels arising from the peripheral optic disc) and macular atrophy. Peripapillary chorioretinal atrophy and chorioretinal and iris coloboma have also been described. Patients present with horizontal nystagmus and poor visual acuity.

Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A), which includes both the more severe Walker-Warburg syndrome (WWS) and the slightly less severe muscle-eye-brain disease (MEB), is a genetically heterogeneous autosomal recessive disorder with characteristic brain and eye malformations, profound mental retardation, congenital muscular dystrophy, and early death. The phenotype commonly includes cobblestone (type II) lissencephaly, cerebellar malformations, and retinal malformations. More variable features include macrocephaly or microcephaly, hypoplasia of midline brain structures, ventricular dilatation, microphthalmia, cleft lip/palate, and congenital contractures (Dobyns et al., 1989). Those with a more severe phenotype characterized as Walker-Warburg syndrome often die within the first year of life, whereas those characterized as having muscle-eye-brain disease may rarely acquire the ability to walk and to speak a few words. These are part of a group of disorders resulting from defective glycosylation of DAG1 (128239), collectively known as 'dystroglycanopathies' (Godfrey et al., 2007). Genetic Heterogeneity of Congenital Muscular Dystrophy-Dystroglycanopathy with Brain and Eye Anomalies (Type A) Muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A) is genetically heterogeneous and can be caused by mutation in other genes involved in DAG1 glycosylation: see MDDGA2 (613150), caused by mutation in the POMT2 gene (607439); MDDGA3 (253280), caused by mutation in the POMGNT1 gene (606822); MDDGA4 (253800), caused by mutation in the FKTN gene (607440); MDDGA5 (613153), caused by mutation in the FKRP gene (606596); MDDGA6 (613154), caused by mutation in the LARGE gene (603590); MDDGA7 (614643), caused by mutation in the ISPD gene (CRPPA; 614631); MDDGA8 (614830) caused by mutation in the GTDC2 gene (POMGNT2; 614828); MDDGA9 (616538), caused by mutation in the DAG1 gene (128239); MDDGA10 (615041), caused by mutation in the TMEM5 gene (RXYLT1; 605862); MDDGA11 (615181), caused by mutation in the B3GALNT2 gene (610194); MDDGA12 (615249), caused by mutation in the SGK196 gene (POMK; 615247); MDDGA13 (615287), caused by mutation in the B3GNT1 gene (B4GAT1; 605517); and MDDGA14 (615350), caused by mutation in the GMPPB gene (615320).

Congenital disorder of glycosylation with defective fucosylation is an autosomal recessive multisystem disorder apparent from birth. Affected infants have poor growth, failure to thrive, hypotonia, skeletal anomalies, and delayed psychomotor development with intellectual disability. Additional highly variable congenital defects may be observed (summary by Ng et al., 2018). Genetic Heterogeneity of Congenital Disorders of Glycosylation with Defective Fucosylation See also CDGF2 (618323), caused by mutation in the FCSK gene (608675) on chromosome 16q22. For an overview of congenital disorders of glycosylation (CDG), see CDG1A (212065) and CDG2A (212066).

Khan-Khan-Katsanis syndrome (3KS) is an autosomal recessive neurodevelopmental disorder with variable involvement of the ocular, renal, skeletal, and sometimes cardiac systems. Affected individuals present at birth with multiple congenital anomalies, defects in urogenital and limb morphogenesis, poor overall growth with microcephaly, and global developmental delay (summary by Khan et al., 2019).

Cerebellar, ocular, craniofacial, and genital syndrome (COFG) is characterized by moderate to severe developmental delay and impaired intellectual development, severe cerebellar hypoplasia, a noticeably short forehead, medially sparse/flared and laterally extended eyebrows, corneal dystrophy, underdeveloped labioscrotal folds, and tufts of hair extruding from the lactiferous ducts with breast and nipple underdevelopment. Additional features such as pontine involvement, retinal degeneration, anteverted nares, and low-set ears have been variably observed (Rad et al., 2019).