Hypotrichosis–acro-osteolysis–onychogryphosis–palmoplantar keratoderma–periodontitis syndrome (also known as "HOPP syndrome") is a cutaneous condition characterized by a prominent palmoplantar keratoderma.

Clinically, three distinct patterns of palmoplantar keratoderma may be identified: diffuse, focal, and punctate.

Hidrotic ectodermal dysplasia 2, or Clouston syndrome (referred to as HED2 throughout this entry) is characterized by partial or total alopecia, dystrophy of the nails, hyperpigmentation of the skin (especially over the joints), and clubbing of the fingers. Sparse scalp hair and dysplastic nails are seen early in life. In infancy, scalp hair is wiry, brittle, patchy, and pale; 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. The clinical manifestations are highly variable even within the same family.

Diffuse palmoplantar keratoderma is a type of palmoplantar keratoderma that is characterized by an even, thick, symmetric hyperkeratosis over the whole of the palm and sole, usually evident at birth or in the first few months of life. Restated, diffuse palmoplantar keratoderma is an autosomal dominant disorder in which hyperkeratosis is confined to the palms and soles. The two major types can have a similar clinical appearance:

- "Diffuse epidermolytic palmoplantar keratoderma" (also known as "Palmoplantar keratoderma cum degeneratione granulosa Vörner," "Vörner's epidermolytic palmoplantar keratoderma", and "Vörner keratoderma") is one of the most common patterns of palmoplantar keratoderma, an autosomal dominant condition that presents within the first few months of life, characterized by a well-demarcated, symmetric thickening of palms and soles, often with a "dirty" snakeskin appearance due to underlying epidermolysis.

- "Diffuse nonepidermolytic palmoplantar keratoderma" (also known as "Diffuse orthohyperkeratotic keratoderma," "Hereditary palmoplantar keratoderma," "Keratosis extremitatum progrediens," "Keratosis palmoplantaris diffusa circumscripta," "Tylosis," "Unna–Thost disease", and "Unna–Thost keratoderma") is inherited as an autosomal dominant condition and is present from infancy, characterized by a well-demarcated, symmetric, often "waxy" keratoderma involving the whole of the palms and soles.

Lelis syndrome it is a genetic disorder, a rare condition with dermatological and dental findings characterized by the association of ectodermal dysplasia (hypotrichosis and hypohidrosis) with acanthosis nigricans. Other clinical features may include palmoplantar hyperkeratosis, nail dystrophy, intellectual deficit, disturbances of skin pigmentation (perioral and periorbital hyperpigmentation, vitiligo, and perinevic leukoderma) and hypodontia. Transmission is autosomal recessive.

Corneodermatosseous syndrome (also known as "CDO syndrome") is an autosomal dominant condition with onset in infancy, characterized by corneal dystrophy, photophobia, diffuse palmoplantar keratoderma, distal onycholysis, skeletal abnormalities, with brachydactyly, short stature, and medullary narrowing of digits.

Common symptoms include:

- Excess keratin in nail beds and thickening of the nails

- Hyperkeratosis on hands and feet

- Oral lesions that look like thick white plaques

- Steatocystoma multiplex

- Pain

- Blisters

Meleda disease (MDM) or "mal de Meleda", also called Mljet disease, keratosis palmoplantaris and transgradiens of Siemens, (also known as "Acral keratoderma," "Mutilating palmoplantar keratoderma of the Gamborg-Nielsen type," "Palmoplantar ectodermal dysplasia type VIII", and "Palmoplantar keratoderma of the Norrbotten type") is an extremely rare autosomal recessive congenital skin disorder in which dry, thick patches of skin develop on the soles of the hands and feet, a condition known as palmoplantar hyperkeratosis.

Hystrix-like ichthyosis–deafness syndrome (also known as "HID syndrome") is a cutaneous condition characterized by a keratoderma.

Bart–Pumphrey syndrome (also known as "Palmoplantar keratoderma with knuckle pads and leukonychia and deafness") is a cutaneous condition characterized by hyperkeratoses (knuckle pads) over the metacarpophalangeal, proximal and distal interphalangeal joints.

It was characterized in 1967.

It can be associated with GJB2.

The differential diagnosis is quite extensive and includes

- Buschke–Fischer–Brauer disease

- Curth–Macklin ichthyosis

- Gamborg Nielsen syndrome

- Greither disease

- Haber syndrome

- Hereditary punctate palmoplantar keratoderma

- Jadassohn–Lewandowsky syndrome

- Keratosis follicularis spinulosa decalvans

- Keratosis linearis with ichthyosis congenital and sclerosing keratoderma syndrome

- Meleda disease

- Mucosa hyperkeratosis syndrome

- Naegeli–Franceschetti–Jadassohn syndrome

- Naxos disease

- Olmsted syndrome

- Palmoplantar keratoderma and leukokeratosis anogenitalis

- Pandysautonomia

- Papillomatosis of Gougerot and Carteaud

- Papillon–Lefèvre syndrome

- Punctate porokeratotic keratoderma

- Richner–Hanhart syndrome

- Schöpf–Schulz–Passarge syndrome

- Unna Thost disease

- Vohwinkel syndrome

- Wong's dermatomyositis

Haim–Munk syndrome (also known as "palmoplantar keratoderma with periodontitis and arachnodactyly and acro-osteolysis") is a cutaneous condition caused by a mutation in the cathepsin C gene. It was named after Dr. Salim Haim and Dr. Munk.

Not all of the DOOR symptoms are consistently present. They can vary in severity, and additional features can be noted in individuals affected by DOOR syndrome.

Some of these additional features are:

- Polyhydramnios (increased amniotic fluid during pregnancy) and increased nuchal fold during pregnancy

- Specific facial features such as a large nose

- Severe and sometimes refractory seizures, abnormalities on the magnetic resonance imaging of the brain

- Increased 2-oxoglutaric acid in the blood and urine - this compound is made or used by several enzymes

- Finger-like thumbs

- Visual impairment

- Peripheral neuropathy (nerves conducting sensation from extremities to the brain) and insensivity to pain

Intellectual impairment is present in all reported cases, but the severity can vary widely. The prognosis in terms of survival also varies greatly from early childhood till adulthood.

Schöpf–Schulz–Passarge syndrome (also known as "eyelid cysts, palmoplantar keratoderma, hypodontia, and hypotrichosis") is an autosomal recessive condition with diffuse symmetric palmoplantar keratoderma, with the palmoplantar keratoderma and fragility of the nails beginning around age 12. In addition to palmoplantar keratoderma, other symptoms include hypodontia, hypotrichosis, nail dystrophies, and eyelid cysts (apocrine hidrocystomas). Patients may also develop syringofibroadenoma and squamous cell carcinomas.

It was characterized in 1971.

It has been associated with WNT10A.

Clouston's hidrotic ectodermal dysplasia (also known as "Alopecia congenita with keratosis palmoplantaris," "Clouston syndrome," "Fischer–Jacobsen–Clouston syndrome," "Hidrotic ectodermal dysplasia," "Keratosis palmaris with drumstick fingers," and "Palmoplantar keratoderma and clubbing") is caused by mutations in a connexin gene, GJB6 or connexin-30, characterized by scalp hair that is wiry, brittle, and pale, often associated with patchy alopecia.

Naxos disease (also known as "Diffuse non-epidermolytic palmoplantar keratoderma with woolly hair and cardiomyopathy," "Diffuse palmoplantar keratoderma with woolly hair and arrhythmogenic right ventricular cardiomyopathy firstly described in Naxos island by Dr Nikos Protonotarios," and "Naxos disease") is a cutaneous condition characterized by a palmoplantar keratoderma. The prevalence of the syndrome is about 1 person in 1000 in the Hellenic islands.

It has been associated with mutations in the genes encoding desmoplakin and plakoglobin.

Cerebral dysgenesis–neuropathy–ichthyosis–keratoderma syndrome (also known as "CEDNIK syndrome") is a cutaneous condition caused by mutation in the SNAP29 gene.

Pachyonychia congenita may be divided into these types:

- Pachyonychia congenita type I (also known as "Jadassohn–Lewandowsky syndrome") is an autosomal dominant keratoderma that principally involves the plantar surfaces, but also with nails changes that may be evident at birth, but more commonly develop within the first few months of life.

- Pachyonychia congenita type II (also known as "Jackson–Lawler pachyonychia congenita" and "Jackson–Sertoli syndrome") is an autosomal dominant keratoderma presenting with a limited focal plantar keratoderma that may be very minor, with nails changes that may be evident at birth, but more commonly develop within the first few months of life.

Keratitis–ichthyosis–deafness syndrome (also known as "Erythrokeratodermia progressiva Burns," "Ichthyosiform erythroderma, corneal involvement, and deafness," and "KID syndrome,") presents at birth/infancy and is characterized by pregressive corneal opacification, either mild generalized hyperkeratosis or discrete erythematous plaques, and neurosensory deafness.

It is caused by a mutation in connexin 26.

Howel–Evans syndrome is an extremely rare condition involving thickening of the skin in the palms of the hands and the soles of the feet (hyperkeratosis). This familial disease is associated with a high lifetime risk of esophageal cancer. For this reason, it is sometimes known as tylosis with oesophageal cancer (TOC).

The condition is inherited in an autosomal dominant manner, and it has been linked to a mutation in the "RHBDF2" gene. It was first described in 1958.

Focal palmoplantar and gingival keratosis is a rare autosomal dominant disease whose clinical features, and in particular, pathologic alterations and molecular mechanisms remains to be well defined.

DOOR (deafness, onychdystrophy, osteodystrophy, and mental retardation) syndrome is a genetic disease which is inherited in an autosomal recessive fashion. DOOR syndrome is characterized by mental retardation, sensorineural deafness, abnormal nails and phalanges of the hands and feet, and variable seizures. A similar deafness-onychodystrophy syndrome is transmitted as an autosomal dominant trait and has no mental retardation. Some authors have proposed that it may be the same as Eronen Syndrome, but since both disorders are extremely rare it is hard to make a determination.

Fountain syndrome is an autosomal recessive congenital disorder characterized by mental retardation, deafness, skeletal abnormalities and a coarse face with full lips. The abnormal swelling of the cheeks and lips are due to the excessive accumulation of body fluids under the skin. The deafness is due to malformation of the cochlea structure within the inner ear.

PLS is characterized by periodontitis and palmoplantar keratoderma. The severe destruction of periodontium results in loss of most primary teeth by the age of 4 and most permanent teeth by age 14. Hyperkeratosis of palms and soles of feet appear in first few years of life. Destructions of periodontium follows almost immediately after the eruption of last molar tooth. The teeth are involved in roughly the same order in which they erupt.

Albinism–deafness syndrome (also known as "Woolf syndrome" and "Ziprkowski–Margolis syndrome") is a condition characterized by congenital neural deafness and a severe or extreme piebald-like phenotype with extensive areas of hypopigmentation.

A locus at Xq26.3-q27.I has been suggested.

It has been suggested that it is a form of Waardenburg syndrome type II.