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Pachyonychia congenita syndrome(PC)

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: Congenital pachyonychia; PC
SNOMED CT: Pachyonychia congenita syndrome (39427000); Congenital pachyonychia (39427000); Pachyonychia congenita (39427000)
Modes of inheritance:
Autosomal dominant inheritance
MedGen UID:
Concept ID:
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele.
Related genes: KRT17, KRT16, KRT6B, KRT6A
Monarch Initiative: MONDO:0016471
OMIM® Phenotypic series: PS167200
Orphanet: ORPHA2309

Disease characteristics

Excerpted from the GeneReview: Pachyonychia Congenita
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. [from GeneReviews]
Frances JD Smith  |  C David Hansen  |  Peter R Hull, et. al.   view full author information

Additional description

From MedlinePlus Genetics
Pachyonychia congenita is a condition that primarily affects the skin and nails. The signs and symptoms of this condition usually become apparent within the first few years of life.

Almost everyone with pachyonychia congenita develops very painful calluses on the soles of the feet. This condition is known as plantar keratoderma. Calluses usually begin to form on the feet in childhood when kids first start to walk. The calluses can make walking painful or impossible. In some affected individuals, blisters, bundles of blood vessels and nerves (neurovascular structures), or a deep itch may develop under or near the calluses, increasing pain and discomfort.

Most people with pachyonychia congenita also show some signs of hypertrophic nail dystrophy, which causes the fingernails and toenails to become thick and abnormally shaped. The number of affected nails varies.

Pachyonychia congenita can have several additional features. These features include thickened skin on the palms of the hands (palmar keratoderma), which can be painful; thick, white patches on the tongue and inside of the cheeks (oral leukokeratosis); bumps that develop around hair follicles (follicular keratoses) on the elbows, knees, and waistline; cysts in the armpits, groin, back, or scalp; and excessive sweating on the palms and soles (palmoplantar hyperhidrosis).

Some affected individuals also develop widespread cysts called steatocystomas, which are filled with an oily substance called sebum that normally lubricates the skin and hair. Some babies with pachyonychia congenita have prenatal or natal teeth, which are teeth that are present at birth or in early infancy. Some babies and children with pachyonychia congenita have pain in one or both ears when beginning to eat or drink. Pachyonychia congenita can also affect the voice box (larynx), causing hoarseness or breathing problems.

Researchers used to classigy pachyonychia congenita as either PC-1 or PC-2 based on the genetic cause and pattern of signs and symptoms. However, as more affected individuals were identified, it became clear that the signs and symptoms of the types overlapped considerably. Pachyonychia congenita is now classified into five types based on the gene that is altered.  https://medlineplus.gov/genetics/condition/pachyonychia-congenita

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
Follow this link to review classifications for Pachyonychia congenita syndrome in Orphanet.

Professional guidelines


Pinna R, Cocco F, Campus G, Conti G, Milia E, Sardella A, Cagetti MG
Periodontol 2000 2019 Jun;80(1):12-27. doi: 10.1111/prd.12261. PMID: 31090139

Recent clinical studies


Bento RF, Guatimosim MH, Bensadon Rde L, Sanchez TG, Voegels RL
J Laryngol Otol 1996 Dec;110(12):1145-7. doi: 10.1017/s0022215100135972. PMID: 9015428

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