Odontoonychodermal dysplasia (OODD) is an autosomal recessive disorder characterized by dry hair, severe hypodontia, smooth tongue with marked reduction of fungiform and filiform papillae, onychodysplasia, hyperkeratosis of the palms and soles, hypo- and hyperhidrosis of the skin, and atrophic patches on the face (summary by Adaimy et al., 2007; Yu et al., 2019).

A severe form of axonal Charcot-Marie-Tooth disease, a peripheral sensorimotor neuropathy. Onset in the second or third decade has manifestations of ulceration and infection of the feet. Symmetric and distal weakness develops mostly in the legs together with a severe symmetric distal sensory loss. Tendon reflexes are only reduced at ankles and foot deformities including pes cavus or planus and hammer toes, appear in childhood.

Any tooth agenesis in which the cause of the disease is a mutation in the WNT10A gene.

This form of isolated toenail dystrophy has been found to segregate as an autosomal dominant trait in families in which another member has the autosomal recessive skin disorder dystrophic epidermolysis bullosa (226600) or transient bullous dermolysis of the newborn (131705), the features of which include dystrophic nails. The nail changes in isolated toenail dystrophy are most severe in the great toes and consist of the nail plate being buried in the nail bed with a deformed and narrow free edge (summary by Sato-Matsumura et al., 2002). This form of toenail dystrophy is referred to here as nonsyndromic congenital nail disorder-8 (NDNC8). For a list of other nonsyndromic congenital nail disorders and a discussion of genetic heterogeneity, see NDNC1 (161050).

Blepharophimosis-intellectual disability syndrome, Verloes type is a rare, genetic multiple congenital anomalies/dysmorphic syndrome characterized by congenital microcephaly, severe epilepsy with hypsarrhythmia, adducted thumbs, abnormal genitalia, and normal thyroid function. Hypotonia, moderate to severe psychomotor delay, and characteristic facial dysmorphism (including round face with prominent cheeks, blepharophimosis, large, bulbous nose with wide alae nasi, posteriorly rotated ears with dysplastic conchae, narrow mouth, cleft palate, and mild micrognathia) are additional 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-8 is an autosomal recessive disorder characterized by abnormal development of hair, teeth, and nails.

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.

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.

Epidermolysis bullosa simplex (EBS) is characterized by fragility of the skin (and mucosal epithelia in some instances) that results in non-scarring blisters and erosions caused by minor mechanical trauma. EBS is distinguished from other types of epidermolysis bullosa (EB) or non-EB skin fragility syndromes by the location of the blistering in relation to the dermal-epidermal junction. In EBS, blistering occurs within basal keratinocytes. The severity of blistering ranges from limited to hands and feet to widespread involvement. Additional features can include hyperkeratosis of the palms and soles (keratoderma), nail dystrophy, milia, and hyper- and/or hypopigmentation. Rare EBS subtypes have been associated with additional clinical features including pyloric atresia, muscular dystrophy, cardiomyopathy, and/or nephropathy.

Adams-Oliver syndrome (AOS) is characterized by aplasia cutis congenita (ACC) of the scalp and terminal transverse limb defects (TTLD). ACC lesions usually occur in the midline of the parietal or occipital regions, but can also occur on the abdomen or limbs. At birth, an ACC lesion may already have the appearance of a healed scar. ACC lesions less than 5 cm often involve only the skin and almost always heal over a period of months; larger lesions are more likely to involve the skull and possibly the dura, and are at greater risk for complications, which can include infection, hemorrhage, or thrombosis, and can result in death. The limb defects range from mild (unilateral or bilateral short distal phalanges) to severe (complete absence of all toes or fingers, feet or hands, or more, often resembling an amputation). The lower extremities are almost always more severely affected than the upper extremities. Additional major features frequently include cardiovascular malformations/dysfunction (23%), brain anomalies, and less frequently renal, liver, and eye anomalies.

Epidermolysis bullosa simplex (EBS) is characterized by fragility of the skin (and mucosal epithelia in some instances) that results in non-scarring blisters and erosions caused by minor mechanical trauma. EBS is distinguished from other types of epidermolysis bullosa (EB) or non-EB skin fragility syndromes by the location of the blistering in relation to the dermal-epidermal junction. In EBS, blistering occurs within basal keratinocytes. The severity of blistering ranges from limited to hands and feet to widespread involvement. Additional features can include hyperkeratosis of the palms and soles (keratoderma), nail dystrophy, milia, and hyper- and/or hypopigmentation. Rare EBS subtypes have been associated with additional clinical features including pyloric atresia, muscular dystrophy, cardiomyopathy, and/or nephropathy.

Coffin-Siris syndrome is a rare congenital disorder characterized by delayed psychomotor development, intellectual disability, coarse facial features, and hypoplasia of the distal phalanges, particularly the fifth digit. Other features may also be observed, including congenital heart defects, hypoplasia of the corpus callosum, and poor overall growth with short stature and microcephaly (summary by Wieczorek et al., 2013). Patients with SMARCE1 mutations have a wide spectrum of manifestations, including severe to moderate intellectual disability and heart defects (summary by Kosho et al., 2014). For a general phenotypic description and a discussion of genetic heterogeneity of Coffin-Siris syndrome, see CSS1 (135900).

Erythrokeratodermia variabilis et progressiva-7 (EKVP7) is characterized by palmoplantar keratoderma that extends to the dorsal surface of the hands and feet (transgrediens), as well as erythematous annular skin lesions. Pruritis, woolly hair, and dystrophic nails may also be present (Duchatelet et al., 2019; Patel et al., 2020). For a general phenotypic description and discussion of genetic heterogeneity of EKVP, see EKVP1 (133200).

Epidermolysis bullosa simplex (EBS) is characterized by fragility of the skin (and mucosal epithelia in some instances) that results in non-scarring blisters and erosions caused by minor mechanical trauma. EBS is distinguished from other types of epidermolysis bullosa (EB) or non-EB skin fragility syndromes by the location of the blistering in relation to the dermal-epidermal junction. In EBS, blistering occurs within basal keratinocytes. The severity of blistering ranges from limited to hands and feet to widespread involvement. Additional features can include hyperkeratosis of the palms and soles (keratoderma), nail dystrophy, milia, and hyper- and/or hypopigmentation. Rare EBS subtypes have been associated with additional clinical features including pyloric atresia, muscular dystrophy, cardiomyopathy, and/or nephropathy.