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Pachyonychia congenita 2(PC2)

MedGen UID:
314107
Concept ID:
C1721007
Disease or Syndrome
Synonyms: Jackson-Lawler syndrome; KRT17-Related Pachyonychia Congenita; KRT6B-Related Pachyonychia Congenita; Pachyonychia congenita Jackson Lawler type; PC-K17; PC2
 
Gene (location): KRT17 (17q21.2)
 
Monarch Initiative: MONDO:0008174
OMIM®: 167210

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]
Authors:
Frances JD Smith  |  C David Hansen  |  Peter R Hull, et. al.   view full author information

Additional descriptions

From OMIM
Pachyonychia congenita (PC) is an autosomal dominant genodermatosis with the main clinical features of hypertrophic nail dystrophy, painful and highly debilitating plantar keratoderma, oral leukokeratosis, and a variety of epidermal cysts. Although the condition had previously been subdivided clinically into Jadassohn-Lewandowsky PC type 1 and Jackson-Lawler PC type 2, patients with PC were later found to have a mixed constellation of both types, leading to a classification of PC based on genotype (summary by Sybert, 2010; Eliason et al., 2012; McLean et al., 2011). For a discussion of genetic heterogeneity of pachyonychia congenita, see 167200. Historical Classification of Pachyonychia Congenita Gorlin et al. (1976) suggested that 2 distinct syndromes are subsumed under the designation pachyonychia congenita. PC type 1, the Jadassohn-Lewandowsky type, shows oral leukokeratosis. PC type 2, the Jackson-Lawler type, has natal teeth and epidermoid cysts (cylindromas), but no oral leukoplakia. Corneal dystrophy may be a feature exclusively of the Jackson-Lawler type. Smith et al. (1998) stated that PC type 2, in contrast to PC type 1, has minimal oral involvement and milder keratoderma, and multiple steatocystomas (184500) is a major clinical feature. Steatocystoma, also known as eruptive vellus cyst, is a cystic hamartoma lined by sebaceous ductal epithelium. On the basis of a study of 13 patients with PC type 1 or type 2, Terrinoni et al. (2001) concluded that the presence of pilosebaceous cysts following puberty is the best indicator of PC type 2; prepubescent patients are more difficult to classify due to the lack of cysts. Natal teeth are indicative of PC type 2, although their absence does not preclude the PC type 2 diagnosis.  http://www.omim.org/entry/167210
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).

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.

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.   https://medlineplus.gov/genetics/condition/pachyonychia-congenita

Clinical features

From HPO
Steatocystoma multiplex
MedGen UID:
75476
Concept ID:
C0259771
Neoplastic Process
Steatocystoma multiplex is a skin disorder characterized by the development of multiple noncancerous (benign) cysts known as steatocystomas. These growths begin in the skin's sebaceous glands, which normally produce an oily substance called sebum that lubricates the skin and hair. Steatocystomas are filled with sebum.\n\nIn affected individuals, steatocystomas typically first appear during adolescence and are found most often on the torso, neck, upper arms, and upper legs. These cysts are usually the only sign of the condition. However, some affected individuals also have mild abnormalities involving the teeth or the fingernails and toenails.
Palmoplantar keratosis
MedGen UID:
44017
Concept ID:
C0022596
Disease or Syndrome
Abnormal thickening of the skin localized to the palm of the hand and the sole of the foot.
Folliculitis
MedGen UID:
4752
Concept ID:
C0016436
Disease or Syndrome
Inflammatory cells within the wall and ostia of the hair follicle, creating a follicular-based pustule.
Hoarse voice
MedGen UID:
5602
Concept ID:
C0019825
Sign or Symptom
Hoarseness refers to a change in the pitch or quality of the voice, with the voice sounding weak, very breathy, scratchy, or husky.
Oral mucosa leukoplakia
MedGen UID:
9738
Concept ID:
C0023532
Neoplastic Process
A thickened white patch on the oral mucosa that cannot be rubbed off.
Natal tooth
MedGen UID:
10268
Concept ID:
C0027443
Finding
A tooth present at birth or erupting within the first month of life.
Angular cheilitis
MedGen UID:
526202
Concept ID:
C0221237
Disease or Syndrome
A type of inflammation of the lips involving one or both of the corners of the mouth.
Sparse eyebrow
MedGen UID:
371332
Concept ID:
C1832446
Finding
Decreased density/number of eyebrow hairs.
Sparse scalp hair
MedGen UID:
346499
Concept ID:
C1857042
Finding
Decreased number of hairs per unit area of skin of the scalp.
Epidermoid cysts
MedGen UID:
41829
Concept ID:
C0014511
Anatomical Abnormality
Nontender, round and firm, but slightly compressible, intradermal or subcutaneous cyst measuring 0.5-5 cm in diameter. Epidermal cysts are intradermal or subcutaneous tumors, grow slowly and occur on the face, neck, back and scrotum. They usually appear at or around puberty, and as a rule an affected individual has one solitary or a few cysts.
Subungual hyperkeratosis
MedGen UID:
21379
Concept ID:
C0038605
Finding
A thickening of the stratum corneum in the region beneath the nails.
Nail dystrophy
MedGen UID:
66368
Concept ID:
C0221260
Disease or Syndrome
Onychodystrophy (nail dystrophy) refers to nail changes apart from changes of the color (nail dyschromia) and involves partial or complete disruption of the various keratinous layers of the nail plate.
Dry hair
MedGen UID:
75809
Concept ID:
C0277960
Finding
Hair that lacks the luster (shine or gleam) of normal hair.
Palmoplantar hyperhidrosis
MedGen UID:
224808
Concept ID:
C1274743
Disease or Syndrome
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.
Nail dysplasia
MedGen UID:
331737
Concept ID:
C1834405
Congenital Abnormality
The presence of developmental dysplasia of the nail.

Professional guidelines

PubMed

Wu TT, Eldirany SA, Bunick CG, Teng JMC
J Invest Dermatol 2021 Dec;141(12):2876-2884.e4. Epub 2021 Jun 8 doi: 10.1016/j.jid.2021.03.035. PMID: 34116063Free PMC Article
Porter RM, Bravo AA, Smith FJD
J Am Podiatr Med Assoc 2017 Sep;107(5):428-435. doi: 10.7547/16-043. PMID: 29077501
Milstone LM, Fleckman P, Leachman SA, Leigh IM, Paller AS, van Steensel MA, Swartling C
J Investig Dermatol Symp Proc 2005 Oct;10(1):18-20. doi: 10.1111/j.1087-0024.2005.10203.x. PMID: 16250205

Recent clinical studies

Etiology

Chu HT, Dinh Duong TA, Le DH, Le TV, Nguyen BB, Dang CV, Vu QV
Pediatr Neonatol 2023 Jul;64(4):405-410. Epub 2023 Jan 3 doi: 10.1016/j.pedneo.2022.09.018. PMID: 36658016
Martina E, Diotallevi F, Radi G, Campanati A, Offidani A
Toxins (Basel) 2021 Feb 5;13(2) doi: 10.3390/toxins13020120. PMID: 33562846Free PMC Article
Porter RM, Bravo AA, Smith FJD
J Am Podiatr Med Assoc 2017 Sep;107(5):428-435. doi: 10.7547/16-043. PMID: 29077501
McLean WH, Hansen CD, Eliason MJ, Smith FJ
J Invest Dermatol 2011 May;131(5):1015-7. Epub 2011 Mar 24 doi: 10.1038/jid.2011.59. PMID: 21430705
Feinstein A, Friedman J, Schewach-Millet M
J Am Acad Dermatol 1988 Oct;19(4):705-11. doi: 10.1016/s0190-9622(88)70226-1. PMID: 3053803

Diagnosis

Tan Y, Ma DL
Indian J Pediatr 2024 Mar;91(3):300-301. Epub 2023 Jun 8 doi: 10.1007/s12098-023-04567-z. PMID: 37289311
Pavlovsky M, Peled A, Sarig O, Astman N, Malki L, Meijers O, Assaf S, Schwartz J, Malovitski K, Hansen D, Sprecher E, Samuelov L
Br J Dermatol 2022 Sep;187(3):392-400. Epub 2022 Jun 17 doi: 10.1111/bjd.21674. PMID: 35606927Free PMC Article
Steele L, O'Toole EA
Br J Dermatol 2020 Mar;182(3):521-522. doi: 10.1111/bjd.18817. PMID: 32107781
Yang L, Zhang S, Wang G
J Pathol 2019 Feb;247(2):158-165. Epub 2018 Dec 7 doi: 10.1002/path.5178. PMID: 30306595
Piraccini BM, Starace M
Curr Opin Pediatr 2014 Aug;26(4):440-5. doi: 10.1097/MOP.0000000000000116. PMID: 24886951

Therapy

Martina E, Diotallevi F, Radi G, Campanati A, Offidani A
Toxins (Basel) 2021 Feb 5;13(2) doi: 10.3390/toxins13020120. PMID: 33562846Free PMC Article
Piraccini BM, Starace M
Curr Opin Pediatr 2014 Aug;26(4):440-5. doi: 10.1097/MOP.0000000000000116. PMID: 24886951
McLean WH, Moore CB
Hum Mol Genet 2011 Oct 15;20(R2):R189-97. Epub 2011 Sep 2 doi: 10.1093/hmg/ddr379. PMID: 21890491
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J Am Acad Dermatol 1988 Apr;18(4 Pt 1):721-41. doi: 10.1016/s0190-9622(88)70096-1. PMID: 2967311

Prognosis

Samuelov L, Smith FJD, Hansen CD, Sprecher E
Br J Dermatol 2020 Mar;182(3):738-746. Epub 2020 Jan 14 doi: 10.1111/bjd.18794. PMID: 31823354
Yang L, Zhang S, Wang G
J Pathol 2019 Feb;247(2):158-165. Epub 2018 Dec 7 doi: 10.1002/path.5178. PMID: 30306595
Porter RM, Bravo AA, Smith FJD
J Am Podiatr Med Assoc 2017 Sep;107(5):428-435. doi: 10.7547/16-043. PMID: 29077501
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Chen J, Roop DR
J Investig Dermatol Symp Proc 2005 Oct;10(1):37-46. doi: 10.1111/j.1087-0024.2005.10206.x. PMID: 16250208

Clinical prediction guides

Porter RM, Bravo AA, Smith FJD
J Am Podiatr Med Assoc 2017 Sep;107(5):428-435. doi: 10.7547/16-043. PMID: 29077501
Duchatelet S, Hovnanian A
Orphanet J Rare Dis 2015 Mar 17;10:33. doi: 10.1186/s13023-015-0246-5. PMID: 25886873Free PMC Article
Knöbel M, O'Toole EA, Smith FJ
Cell Tissue Res 2015 Jun;360(3):583-9. Epub 2015 Jan 27 doi: 10.1007/s00441-014-2105-4. PMID: 25620412
Leachman SA, Kaspar RL, Fleckman P, Florell SR, Smith FJ, McLean WH, Lunny DP, Milstone LM, van Steensel MA, Munro CS, O'Toole EA, Celebi JT, Kansky A, Lane EB
J Investig Dermatol Symp Proc 2005 Oct;10(1):3-17. doi: 10.1111/j.1087-0024.2005.10202.x. PMID: 16250204
Su WP, Chun SI, Hammond DE, Gordon H
Pediatr Dermatol 1990 Mar;7(1):33-8. doi: 10.1111/j.1525-1470.1990.tb01070.x. PMID: 2140447

Recent systematic reviews

Martina E, Diotallevi F, Radi G, Campanati A, Offidani A
Toxins (Basel) 2021 Feb 5;13(2) doi: 10.3390/toxins13020120. PMID: 33562846Free PMC Article
Tatiane A, Slape D, Lawless R, Frew JW
Clin Exp Dermatol 2019 Aug;44(6):606-612. Epub 2019 May 10 doi: 10.1111/ced.13980. PMID: 31074523
Torchia D, Vega J, Schachner LA
Am J Clin Dermatol 2012 Feb 1;13(1):19-28. doi: 10.2165/11589050-000000000-00000. PMID: 21958358

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