Wieacker-Wolff syndrome (WRWF) is a severe X-linked recessive neurodevelopmental disorder affecting the central and peripheral nervous systems. It is characterized by onset of muscle weakness in utero (fetal akinesia), which results in arthrogryposis multiplex congenita (AMC) apparent at birth. Affected boys are born with severe contractures, show delayed motor development, facial and bulbar weakness, characteristic dysmorphic facial features, and skeletal abnormalities, such as hip dislocation, scoliosis, and foot deformities. Additional features include global developmental delay with poor or absent speech and impaired intellectual development, feeding difficulties and poor growth, hypotonia, hypogenitalism, and spasticity. Carrier females may be unaffected or have mild features of the disorder (summary by Hirata et al., 2013 and Frints et al., 2019).

Epidermolytic palmoplantar keratoderma-1 (EPPK1) is an autosomal dominant skin disorder characterized clinically by diffuse, yellow thickening of the skin of the palms and soles. There is no extension of the keratoderma to dorsal surfaces of hands and feet, inner wrists, and Achilles tendon area (transgrediens). Knuckle pads may be present in some individuals (summary by Kuster et al., 2002, Chiu et al., 2007). Genetic Heterogeneity of Epidermolytic Palmoplantar Keratoderma Epidermolytic palmoplantar keratoderma-2 (EPPK2; 620411) is caused by mutation in the keratin-1 gene (KRT1; 139350) on chromosome 12q13. Classification of Palmoplantar Keratoderma PPK has been classified into diffuse, focal, and punctate forms according to the pattern of hyperkeratosis on the palms and soles (Lucker et al., 1994). Diffuse PPK develops at birth or shortly thereafter and involves the entire palm and sole with a sharp cutoff at an erythematous border; there are no lesions outside the volar skin, and, in particular, no follicular or oral lesions. In contrast, focal PPK is a late-onset form in which focal hyperkeratotic lesions develop in response to mechanical trauma; an important distinguishing feature is the presence of lesions at other body sites, e.g., oral and follicular hyperkeratosis (Stevens et al., 1996). Palmoplantar keratodermas can be further subdivided histologically into epidermolytic and nonepidermolytic PPK (Risk et al., 1994). Genetic Heterogeneity of Palmoplantar Keratoderma Nonepidermolytic palmoplantar keratoderma (NEPPK; 600962) is caused by mutation in the KRT1 gene. A focal form of NEPPK (FNEPPK1; 613000) is caused by mutation in the KRT16 gene (148067). Another focal form, FNEPPK2 (616400), is caused by mutation in the TRPV3 gene (607066); mutation in TRPV3 can also cause Olmsted syndrome (OLMS; 614594), a severe mutilating form of PPK. The diffuse Bothnian form of NEPPK (PPKB; 600231) is caused by mutation in the AQP5 gene (600442). The Nagashima type of nonepidermolytic diffuse PPK (PPKN; 615598) is caused by mutation in the SERPINB7 gene (603357). A generalized form of epidermolytic hyperkeratosis (EHK; 113800), also designated bullous congenital ichthyosiform erythroderma (BCIE), is caused by mutation in the keratin genes KRT1 and KRT10 (148080). For a discussion of punctate PPK, see 148600; for a discussion of striate PPK, see 148700.

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

Isolated congenital adermatoglyphia is a rare, genetic developmental defect during embryogenesis disorder characterized by the lack of epidermal ridges on the palms and soles, resulting in the absence of fingerprints, with no other associated manifestations. It is associated with a reduced number of sweat gland openings and reduced transpiration of palms and soles.

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.

Pachyonychia congenita (PC) is characterized by hypertrophic nail dystrophy, painful palmoplantar keratoderma and blistering, oral leukokeratosis, pilosebaceous cysts (including steatocystoma and vellus hair cysts), palmoplantar hyperhydrosis, and follicular keratoses on the trunk and extremities.