Ellis-van Creveld syndrome is an autosomal recessive skeletal dysplasia characterized by short limbs, short ribs, postaxial polydactyly, and dysplastic nails and teeth. Congenital cardiac defects, most commonly a defect of primary atrial septation producing a common atrium, occur in 60% of affected individuals (summary by Ruiz-Perez et al., 2000). The clinical features of the Ellis-van Creveld syndrome appear to be identical regardless of whether the disorder is caused by mutation in the EVC gene (604831) or in the EVC2 gene (607261) (Ruiz-Perez et al., 2003, Galdzicka et al., 2002).

Hidrotic ectodermal dysplasia 2, or Clouston syndrome (referred to as HED2 throughout this GeneReview) is characterized by a triad of major clinical features including partial-to-complete alopecia, nail dystrophy, and palmoplantar hyperkeratosis. Sweating is preserved and there are usually no dental anomalies. Sparse scalp hair and dysplastic nails are seen early in life. In infancy, scalp hair is fine, sparse, and brittle. Progressive hair loss may lead to total alopecia by puberty. The nails may be milky white in early childhood; they gradually become dystrophic, thick, and distally separated from the nail bed. Palmoplantar keratoderma may develop during childhood and increases in severity with age. Associated features may include cutaneous hyperpigmentation (particularly over the joints) and finger clubbing. The clinical manifestations are highly variable even within the same family.

A rare genetic disease characterized by lipoatrophic diabetes, mild craniofacial dysmorphism (such as pronounced antitragal incisura and mandibular prognathism), ectodermal dysplasia (generalized hypotrichosis and dental and nail abnormalities), hypoplasia or aplasia of the breasts, and urogenital/renal anomalies. Additional reported manifestations include skeletal abnormalities and hepatosplenomegaly.

Complete congenital absence of dermatoglyphs is a rare syndrome characterized by autosomal dominant inheritance of the lack of ridges on palms and soles, neonatal acral blisters and facial milia, adult traumatic blistering and fissuring, absent or reduced sweating of palms and soles, and contracture of digits. Additional features may include single palmar transverse crease, palmoplantar keratoderma, and nail grooving (summary by Limova et al., 1993).

The TP63-related disorders comprise six overlapping phenotypes: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome (which includes Rapp-Hodgkin syndrome). Acro-dermo-ungual-lacrimal-tooth (ADULT) syndrome. Ectrodactyly, ectodermal dysplasia, cleft lip/palate syndrome 3 (EEC3). Limb-mammary syndrome. Split-hand/foot malformation type 4 (SHFM4). Isolated cleft lip/cleft palate (orofacial cleft 8). Individuals typically have varying combinations of ectodermal dysplasia (hypohidrosis, nail dysplasia, sparse hair, tooth abnormalities), cleft lip/palate, split-hand/foot malformation/syndactyly, lacrimal duct obstruction, hypopigmentation, hypoplastic breasts and/or nipples, and hypospadias. Findings associated with a single phenotype include ankyloblepharon filiforme adnatum (tissue strands that completely or partially fuse the upper and lower eyelids), skin erosions especially on the scalp associated with areas of scarring, and alopecia, trismus, and excessive freckling.

Cranioectodermal dysplasia (CED) is a ciliopathy with skeletal involvement (narrow thorax, shortened proximal limbs, syndactyly, polydactyly, brachydactyly), ectodermal features (widely spaced hypoplastic teeth, hypodontia, sparse hair, skin laxity, abnormal nails), joint laxity, growth deficiency, and characteristic facial features (frontal bossing, low-set simple ears, high forehead, telecanthus, epicanthal folds, full cheeks, everted lower lip). Most affected children develop nephronophthisis that often leads to end-stage kidney disease in infancy or childhood, a major cause of morbidity and mortality. Hepatic fibrosis and retinal dystrophy are also observed. Dolichocephaly, often secondary to sagittal craniosynostosis, is a primary manifestation that distinguishes CED from most other ciliopathies. Brain malformations and developmental delay may also occur.

A rare disorder with manifestation of hypo or oligodontia and acanthosis nigricans. It has been described in four generations of one family. Onset generally occurs during adolescence. Some patients are born with multiple teeth. Hair anomalies (sparse body and scalp hair) also reported. Inheritance is autosomal dominant.

Ectodermal dysplasia with immunodeficiency-1 (EDAID1) is an X-linked recessive disorder that characteristically affects only males. Affected individuals have onset of recurrent severe infections due to immunodeficiency in early infancy or in the first years of life. There is increased susceptibility to bacterial, pneumococcal, mycobacterial, and fungal infections. Laboratory studies usually show dysgammaglobulinemia with low IgG subsets and normal or increased IgA and IgM, consistent with impaired 'class-switching' of B cells, although immunologic abnormalities may be subtle compared to the clinical picture, and B- and T-cell numbers are usually normal. There is a poor antibody response to polysaccharide vaccinations, particularly pneumococcus; response to other vaccinations is variable. Patients also have features of ectodermal dysplasia, including conical incisors, hypo/anhidrosis, and thin skin or hair. Severely affected individuals may also show lymphedema, osteopetrosis, and, rarely, hematologic abnormalities. The phenotype is highly variable, likely due to different hypomorphic mutations, and may be fatal in childhood. Intravenous immunoglobulins and prophylactic antibiotics are used as treatment; some patients may benefit from bone marrow transplantation. Although only males tend to be affected with immunodeficiency, many patients inherit a mutation from a mother who has mild features of IP or conical teeth (summary by Doffinger et al., 2001, Orange et al., 2004, Roberts et al., 2010, Heller et al., 2020). Genetic Heterogeneity of Ectodermal Dysplasia and Immune Deficiency Also see EDAID2 (612132), caused by mutation in the NFKBIA gene (164008).

A rare multiple congenital anomalies/dysmorphic syndrome characterized by intellectual disability, severe visual impairment due to ocular malformations (microphthalmos and microcornea with sclerocornea), short stature, hypotrichosis, dental anomalies, and dysmorphic facial features (such as a narrow nasal bridge with marked distal flaring and low-set, protruding ears). There have been no further descriptions in the literature since 1992.

An EEC syndrome characterized by autosomal dominant inheritance that has material basis in variation in the chromosome region 7q11.2-q21.3.

Dermo-odonto dysplasia belongs to the group of tricho-odonto-onychial dysplasia. It has signs of variable severity: dry and thin skin, dental anomalies, nail alteration and trichodysplasia.

EEM syndrome denotes a disorder characterized by ectodermal dysplasia, ectrodactyly, and macular dystrophy. The ectodermal dysplasia consists of hypotrichosis affecting scalp hair, eyebrows, and eyelashes, with partial anodontia. Different degrees of absence deformities as well as syndactyly have been described, the hands often being more severely affected than the feet. The retinal lesion appears as a central geographic atrophy of the retinal pigment epithelium and choriocapillary layer of the macular area with coarse hyperpigmentations and sparing of the larger choroidal vessels (summary by Kjaer et al., 2005).

Schopf-Schulz-Passarge syndrome (SSPS) is an autosomal recessive disorder characterized by a constellation of multiple eyelid cysts, hypodontia, hypotrichosis, palmoplantar hyperkeratosis, and onychodystrophy (summary by Mallaiah and Dickinson, 2001).

A rare genetic ectodermal dysplasia syndrome with characteristics of conductive hearing loss due to atresia of the external auditory canal and the middle ear complicated by chronic infection, ptosis and skeletal anomalies (internal rotation of hips, dislocation of the radial heads and fifth finger clinodactyly). In addition, a thin, pinched nose, delayed hair growth and dysplastic teeth are associated. There have been no further descriptions in the literature since 1978.

Ectodermal dysplasia/skin fragility syndrome (EDSFS) is an autosomal recessive genodermatosis characterized by widespread skin fragility, alopecia, nail dystrophy, and focal keratoderma with painful fissures. Hypohidrosis and cheilitis are sometimes present (summary by Ersoy-Evans et al., 2006).

The TP63-related disorders comprise six overlapping phenotypes: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome (which includes Rapp-Hodgkin syndrome). Acro-dermo-ungual-lacrimal-tooth (ADULT) syndrome. Ectrodactyly, ectodermal dysplasia, cleft lip/palate syndrome 3 (EEC3). Limb-mammary syndrome. Split-hand/foot malformation type 4 (SHFM4). Isolated cleft lip/cleft palate (orofacial cleft 8). Individuals typically have varying combinations of ectodermal dysplasia (hypohidrosis, nail dysplasia, sparse hair, tooth abnormalities), cleft lip/palate, split-hand/foot malformation/syndactyly, lacrimal duct obstruction, hypopigmentation, hypoplastic breasts and/or nipples, and hypospadias. Findings associated with a single phenotype include ankyloblepharon filiforme adnatum (tissue strands that completely or partially fuse the upper and lower eyelids), skin erosions especially on the scalp associated with areas of scarring, and alopecia, trismus, and excessive freckling.

The TP63-related disorders comprise six overlapping phenotypes: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome (which includes Rapp-Hodgkin syndrome). Acro-dermo-ungual-lacrimal-tooth (ADULT) syndrome. Ectrodactyly, ectodermal dysplasia, cleft lip/palate syndrome 3 (EEC3). Limb-mammary syndrome. Split-hand/foot malformation type 4 (SHFM4). Isolated cleft lip/cleft palate (orofacial cleft 8). Individuals typically have varying combinations of ectodermal dysplasia (hypohidrosis, nail dysplasia, sparse hair, tooth abnormalities), cleft lip/palate, split-hand/foot malformation/syndactyly, lacrimal duct obstruction, hypopigmentation, hypoplastic breasts and/or nipples, and hypospadias. Findings associated with a single phenotype include ankyloblepharon filiforme adnatum (tissue strands that completely or partially fuse the upper and lower eyelids), skin erosions especially on the scalp associated with areas of scarring, and alopecia, trismus, and excessive freckling.

Immunodeficiency-9 (IMD9) is an autosomal recessive disorder characterized by early onset of recurrent infections due to defective T-cell activation. Affected individuals also have congenital myopathy resulting in muscle weakness as well as features of ectodermal dysplasia, including soft dental enamel (summary by McCarl et al., 2009).

A rare genetic disease characterized by intellectual disability, growth delay, absence deformities of upper and lower limbs, hypotrichosis, hypoplastic nails, abnormal dentition, abnormal auricles, hypoplastic nipples, thyroid enlargement, and abnormalities of tyrosine and/or tryptophane metabolism. Hypogonadism and cleft lip have also been reported. No new cases have been confirmed since 1970.

Zlotogora-Ogur syndrome is an ectodermal dysplasia syndrome with characteristics of hair, skin and teeth anomalies, facial dysmorphism with cleft lip and palate, cutaneous syndactyly and, in some cases, intellectual disability.The prevalence is unknown but to date, less than 50 cases have been described in the literature. Caused by mutations in the gene PVRL1 (11q23-q24) which encodes nectin-1, the principal receptor used by alpha-herpesviruses to mediate entry into human cells. Transmission is autosomal recessive.

Ectodermal dysplasia-syndactyly syndrome (EDSS) is characterized by sparse to absent scalp hair, eyebrows, and eyelashes, hypoplastic nails, tooth enamel hypoplasia, conical-shaped teeth, palmoplantar keratoderma, and partial cutaneous syndactyly (summary by Raza et al., 2015). Genetic Heterogeneity of Ectodermal Dysplasia-Syndactyly Syndrome Ectodermal dysplasia-syndactyly syndrome-2 (EDSS2; 613576) maps to chromosome 7p21-p14.

Cranioectodermal dysplasia (CED) is a ciliopathy with skeletal involvement (narrow thorax, shortened proximal limbs, syndactyly, polydactyly, brachydactyly), ectodermal features (widely spaced hypoplastic teeth, hypodontia, sparse hair, skin laxity, abnormal nails), joint laxity, growth deficiency, and characteristic facial features (frontal bossing, low-set simple ears, high forehead, telecanthus, epicanthal folds, full cheeks, everted lower lip). Most affected children develop nephronophthisis that often leads to end-stage kidney disease in infancy or childhood, a major cause of morbidity and mortality. Hepatic fibrosis and retinal dystrophy are also observed. Dolichocephaly, often secondary to sagittal craniosynostosis, is a primary manifestation that distinguishes CED from most other ciliopathies. Brain malformations and developmental delay may also occur.

Cranioectodermal dysplasia (CED) is a ciliopathy with skeletal involvement (narrow thorax, shortened proximal limbs, syndactyly, polydactyly, brachydactyly), ectodermal features (widely spaced hypoplastic teeth, hypodontia, sparse hair, skin laxity, abnormal nails), joint laxity, growth deficiency, and characteristic facial features (frontal bossing, low-set simple ears, high forehead, telecanthus, epicanthal folds, full cheeks, everted lower lip). Most affected children develop nephronophthisis that often leads to end-stage kidney disease in infancy or childhood, a major cause of morbidity and mortality. Hepatic fibrosis and retinal dystrophy are also observed. Dolichocephaly, often secondary to sagittal craniosynostosis, is a primary manifestation that distinguishes CED from most other ciliopathies. Brain malformations and developmental delay may also occur.

Hypohidrotic ectodermal dysplasia (HED) is characterized by hypotrichosis (sparseness of scalp and body hair), hypohidrosis (reduced ability to sweat), and hypodontia (congenital absence of teeth). The cardinal features of classic HED become obvious during childhood. The scalp hair is thin, lightly pigmented, and slow growing. Sweating, although present, is greatly deficient, leading to episodes of hyperthermia until the affected individual or family acquires experience with environmental modifications to control temperature. Only a few abnormally formed teeth erupt, at a later-than-average age. Physical growth and psychomotor development are otherwise within normal limits. Mild HED is characterized by mild manifestations of any or all the characteristic features.

Some ectodermal dysplasias are here classified as congenital disorders characterized by abnormal development in 2 or more ectodermal structures (hair, nails, teeth, and sweat glands) without other systemic findings. Ectodermal dysplasia of the hair/nail type is a rare congenital condition characterized by hypotrichosis and nail dystrophy without nonectodermal or other ectodermal manifestations. Hypotrichosis usually occurs after birth with varying degrees of severity, ranging from mild hair loss to complete atrichia, including the loss of scalp hair, beard, eyebrows, eyelashes, axillary hair, and pubic hair. Nail dystrophy affects all 20 digits by causing short fragile nails or spoon nails (koilonychia) (summary by Lin et al., 2012).

Multiple self-healing palmoplantar carcinoma (MSPC) is characterized by recurrent keratoacanthomas in palmoplantar skin as well as in conjunctival and corneal epithelia. In addition, patients experience a high susceptibility to malignant squamous cell carcinoma (summary by Zhong et al., 2016).

Hypohidrotic ectodermal dysplasia (HED) is characterized by hypotrichosis (sparseness of scalp and body hair), hypohidrosis (reduced ability to sweat), and hypodontia (congenital absence of teeth). The cardinal features of classic HED become obvious during childhood. The scalp hair is thin, lightly pigmented, and slow growing. Sweating, although present, is greatly deficient, leading to episodes of hyperthermia until the affected individual or family acquires experience with environmental modifications to control temperature. Only a few abnormally formed teeth erupt, at a later-than-average age. Physical growth and psychomotor development are otherwise within normal limits. Mild HED is characterized by mild manifestations of any or all the characteristic features.

Some ectodermal dysplasias are here classified as congenital disorders characterized by abnormal development in 2 or more ectodermal structures (hair, nails, teeth, and sweat glands) without other systemic findings. Ectodermal dysplasia-13 of the hair/tooth type is characterized by severe oligodontia accompanied by anomalies of hair and skin (Issa et al., 2016).

The IFAP/BRESHECK syndrome is an X-linked multiple congenital anomaly disorder with variable severity. The classic triad, which defines IFAP, is ichthyosis follicularis, atrichia, and photophobia. Some patients have additional features, including mental retardation, brain anomalies, Hirschsprung disease, corneal opacifications, kidney dysplasia, cryptorchidism, cleft palate, and skeletal malformations, particularly of the vertebrae, which constitutes BRESHECK syndrome (summary by Naiki et al., 2012). Genetic Heterogeneity of IFAP Syndrome IFAP syndrome-2 (IFAP2; 619016) is caused by heterozygous mutation in the SREBF1 gene (184756) on chromosome 17p11.