Hyperhidrosis palmaris et plantaris (HYPRPP) is characterized by excessive perspiration of the eccrine sweat gland in the palm, sole, and axilla. Perspiration in those affected may be aggravated by emotional stimuli (summary by Higashimoto et al., 2006). Stolman (1998) noted that hyperhidrosis may be complicated by skin maceration as well as secondary microbial infections, and that treatment modalities are associated with complications.

Keratolytic winter erythema, also known as Oudtshoorn skin disease, manifests during childhood with recurrent episodes of palmoplantar erythema and centrifugal epidermal peeling. Lateral and dorsal aspects of the hands and feet can be involved. A less common finding is a slowly migratory, annular erythema that is seen mostly on the extremities. Between flares, the skin may appear unremarkable. Hyperhidrosis, associated with a pungent odor, is invariably present, and itching can occur. Peeling is preceded by the formation of dry blisters due to keratolysis, whereas formation of vesicles or bullae is rare. Cold weather, moisture, febrile diseases, and physical and mental stress can trigger exacerbations. In severely affected individuals, skin manifestations persist unremittingly. Penetrance of the disease is high, but expressivity is variable, even within the same family (summary by Ngcungcu et al., 2017).

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).

Hyperhidrosis palmaris et plantaris (HYPRPP) is characterized by excessive perspiration of the eccrine sweat gland in the palm, sole, and axilla. Perspiration in those affected may be aggravated by emotional stimuli (summary by Higashimoto et al., 2006). Stolman (1998) noted that hyperhidrosis may be complicated by skin maceration as well as secondary microbial infections, and that treatment modalities are associated with complications.

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.

Hereditary distal onycholysis is an autosomal dominant nail disorder characterized by a decreased rate of growth of the nail, scleronychia, and a straight or concave proximal edge of detachment. Clinical features may include palmoplantar hyperhydrosis and marked sensitivity of the fingers to cold (summary by Bazex et al., 1990). Hereditary distal onycholysis is referred to here as nonsyndromic congenital nail disorder-5 (NDNC5). For a list of other nonsyndromic congenital nail disorders and a discussion of genetic heterogeneity, see NDNC1 (161050).

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

A group of rare autosomal recessive forms of ichthyosis with clinical characteristics of superficial, asymptomatic, spontaneous peeling of the skin and histologically by a shedding of the outer layers of the epidermis. Presents with either an acral or a generalised distribution.

Palmoplantar keratoderma-XX sex reversal-predisposition to squamous cell carcinoma syndrome is characterised by sex reversal in males with a 46, XX (SRY-negative) karyotype, palmoplantar hyperkeratosis and a predisposition to squamous cell carcinoma. To date, five cases (four of whom were brothers) have been described. The aetiology is unknown.

Nagashima-type palmoplantar keratoderma is an autosomal recessive nonsyndromic diffuse palmoplantar keratosis, first described by Nagashima (1977) in the Japanese literature. It is characterized by well-demarcated diffuse erythematous hyperkeratosis that extends onto the dorsal surfaces of the palms and feet and the Achilles tendon area. Involvement of the elbows and knees has also been reported, and there is a high frequency of hyperhidrosis on the palms and soles. In contrast to other types of transgressive diffuse hyperkeratosis such as mal de Meleda (248300), PPKN shows only mild hyperkeratosis that is nonprogressive after the second decade and does not involve flexion contractures or constricting bands (summary by Kubo et al., 2013). For a discussion of phenotypic and genetic heterogeneity of palmoplantar keratoderma, see epidermolytic PPK (144200).

Neurodevelopmental disorder with progressive microcephaly, spasticity, and brain anomalies (NDMSBA) is an autosomal recessive neurodevelopmental disorder characterized by infantile onset of progressive microcephaly and spasticity and severe global developmental delay resulting in profoundly impaired intellectual development and severely impaired or absent motor function. More variable features include seizures and optic atrophy. Brain imaging may show myelinating abnormalities and white matter lesions consistent with a leukoencephalopathy, as well as structural anomalies, including thin corpus callosum, gyral abnormalities, and cerebral or cerebellar atrophy. Some patients die in early childhood (summary by Falik Zaccai et al., 2017 and Hall et al., 2017).