Waardenburg syndrome type 3 is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, skin, and eyes; congenital sensorineural hearing loss; presence of 'dystopia canthorum,' the lateral displacement of the ocular inner canthi; and upper limb abnormalities (reviews by Read and Newton, 1997 and Pingault et al., 2010). WS type 3 is also referred to as 'Klein-Waardenburg syndrome' (Gorlin et al., 1976). Clinical Variability of Waardenburg Syndrome Types 1-4 Waardenburg syndrome has been classified into 4 main phenotypes. Type I Waardenburg syndrome (WS1; 193500) is characterized by pigmentary abnormalities of the hair, including a white forelock and premature graying; pigmentary changes of the iris, such as heterochromia iridis and brilliant blue eyes; congenital sensorineural hearing loss; and 'dystopia canthorum.' WS type II (WS2) is distinguished from type I by the absence of dystopia canthorum. WS type III has dystopia canthorum and is distinguished by the presence of upper limb abnormalities. WS type IV (WS4; 277580), also known as Waardenburg-Shah syndrome, has the additional feature of Hirschsprung disease (reviews by Read and Newton, 1997 and Pingault et al., 2010).

Piebaldism is a rare autosomal dominant trait characterized by the congenital absence of melanocytes in affected areas of the skin and hair. A white forelock of hair, often triangular in shape, may be the only manifestation, or both the hair and the underlying forehead may be involved. The eyebrows and eyelashes may be affected. Irregularly shaped white patches may be observed on the face, trunk, and extremities, usually in a symmetrical distribution. Typically, islands of hyperpigmentation are present within and at the border of depigmented areas (summary by Thomas et al., 2004).

Tietz albinism-deafness syndrome (TADS) is characterized by generalized pigment loss and congenital complete sensorineural hearing loss (summary by Izumi et al., 2008).

PCWH syndrome is a complex neurocristopathy that includes features of 4 distinct syndromes: peripheral demyelinating neuropathy (see 118200), central dysmyelination, Waardenburg syndrome, and Hirschsprung disease (see 142623) (Inoue et al., 2004). Inoue et al. (2004) proposed the acronym PCWH for this disorder.

Waardenburg syndrome type II (WS2) is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, skin, and eyes; congenital sensorineural hearing loss; and the absence of 'dystopia canthorum,' the lateral displacement of the inner canthus of each eye, which is seen in some other forms of WS (Hughes et al., 1994). WS type 2B (WS2B) maps to chromosome 1p. Waardenburg syndrome type 2 is genetically heterogeneous (see WS2A; 193510). For a description of other clinical variants of Waardenburg syndrome, see WS1 (193500), WS3 (148820), and WS4 (277580).

Horner syndrome, resulting from unilateral paralysis of the cervical sympathetics, comprises the classic triad of unilateral ptosis, unilateral miosis with anisocoria, and ipsilateral facial anhidrosis. Iris heterochromia may also be present (Takanashi et al., 2003).

Waardenburg syndrome type I (WS1) is an auditory-pigmentary disorder comprising congenital sensorineural hearing loss and pigmentary disturbances of the iris, hair, and skin along with dystopia canthorum (lateral displacement of the inner canthi). The hearing loss in WS1, observed in approximately 60% of affected individuals, is congenital, typically non-progressive, either unilateral or bilateral, and sensorineural. Most commonly, hearing loss in WS1 is bilateral and profound (>100 dB). The majority of individuals with WS1 have either a white forelock or early graying of the scalp hair before age 30 years. The classic white forelock observed in approximately 45% of individuals is the most common hair pigmentation anomaly seen in WS1. Affected individuals may have complete heterochromia iridium, partial/segmental heterochromia, or hypoplastic or brilliant blue irides. Congenital leukoderma is frequently seen on the face, trunk, or limbs.

Waardenburg syndrome type 4 (WS4), also known as Waardenburg-Shah syndrome, is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, skin, and eyes, congenital sensorineural hearing loss, and Hirschsprung disease (reviews by Read and Newton, 1997 and Pingault et al., 2010). WS type 4A is caused by mutation in the EDNRB gene (131244). Clinical Variability of Waardenburg Syndrome Types 1-4 Waardenburg syndrome has been classified into 4 main phenotypes. Type I Waardenburg syndrome (WS1; 193500) is characterized by pigmentary abnormalities of the hair, including a white forelock and premature graying; pigmentary changes of the iris, such as heterochromia iridis and brilliant blue eyes; congenital sensorineural hearing loss; and 'dystopia canthorum.' WS type II (WS2) is distinguished from type I by the absence of dystopia canthorum. WS type III (WS3; 148820) has dystopia canthorum and is distinguished by the presence of upper limb abnormalities. WS type 4 has the additional feature of Hirschsprung disease (reviews by Read and Newton, 1997 and Pingault et al., 2010). Genetic Heterogeneity of Waardenburg Syndrome Type 4 Waardenburg syndrome type 4 is genetically heterogeneous. WS4B (613265) is caused by mutation in the EDN3 gene (131242) on chromosome 20q13, and WS4C (613266) is caused by mutation in the SOX10 gene (602229) on chromosome 22q13.

Waardenburg syndrome type 2 (WS2) is an autosomal dominant auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, skin, and eyes; congenital sensorineural hearing loss; and the absence of 'dystopia canthorum,' the lateral displacement of the ocular inner canthi, which is seen in some other forms of WS (reviews by Read and Newton, 1997 and Pingault et al., 2010). Clinical Variability of Waardenburg Syndrome Types 1-4 Waardenburg syndrome has been classified into 4 main phenotypes. Waardenburg syndrome type 1 (WS1; 193500) is characterized by pigmentary abnormalities of the hair, including a white forelock and premature graying; pigmentary changes of the iris, such as heterochromia iridis and brilliant blue eyes; congenital sensorineural hearing loss; and 'dystopia canthorum.' WS type 2 (WS2) is distinguished from type 1 by the absence of dystopia canthorum. WS type 3 (WS3; 148820) has dystopia canthorum and is distinguished by the presence of upper limb abnormalities. WS type 4 (WS4; 277580), also known as Waardenburg-Shah syndrome, has the additional feature of Hirschsprung disease (reviews by Read and Newton, 1997 and Pingault et al., 2010). Genetic Heterogeneity of Waardenburg Syndrome Type 2 Waardenburg syndrome type 2 is a genetically heterogeneous disorder. WS2B (600193) has been mapped to chromosome 1p. WS2C (606662) has been mapped to chromosome 8p23. WS2E (611584) is caused by mutation in the SOX10 gene (602229) on chromosome 22q13. WS2F (619947) is caused by mutation in the KITLG gene (184745) on chromosome 12q21. A form of WS2, designated WS2D, was thought to be caused by deletion of the SNAI2 gene (602150.0001), but the deletion has been reclassified as a variant of unknown significance.

Waardenburg syndrome type 2 (WS2) is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, skin, and eyes; congenital sensorineural hearing loss; and the absence of 'dystopia canthorum,' the lateral displacement of the inner canthus of each eye, which is seen in some other forms of WS (review by Read and Newton, 1997). Individuals with WS type 2E (WS2E) may have neurologic abnormalities, including mental impairment, myelination defects, and ataxia. Waardenburg syndrome type 2 is genetically heterogeneous (see WS2A, 193510). For a description of other clinical variants of Waardenburg syndrome, see WS1 (193500), WS3 (148820), and WS4 (277580).

Waardenburg syndrome type 4 is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the eye, deafness, and Hirschsprung disease (review by Read and Newton, 1997). WS type 4C is caused by mutation in the SOX10 gene (602229). WS type 4 is genetically heterogeneous (see WS4A; 277580). For a description of other clinical variants of Waardenburg syndrome, see WS1 (193500), WS2 (193510), and WS3 (148820).

Waardenburg syndrome type 4 is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the eye, deafness, and Hirschsprung disease (review by Read and Newton, 1997). WS type 4B is caused by mutation in the EDN3 gene (131242). WS type 4 is genetically heterogeneous (see WS4A; 277580). For a description of other clinical variants of Waardenburg syndrome, see WS1 (193500), WS2 (193510), and WS3 (148820).

Any autosomal recessive non-syndromic intellectual disability in which the cause of the disease is a mutation in the EDC3 gene.

Waardenburg syndrome type 2F (WS2F) is characterized by congenital or neonatal-onset sensorineural hearing loss and altered pigmentation of the iris, hair, and skin. Variable expressivity has been reported, even among patients with the same mutation (Ogawa et al., 2017; Vona et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of WS2, as well as a brief description of other clinical variants of Waardenburg syndrome (WS1, 193500; WS3, 148820; and WS4, 277580), see WS2A (193510).