Pachyonychia congenita

Infobox_Disease
Name = PAGENAME


Caption =
DiseasesDB = 32826
ICD10 = ICD10|Q|84|5|q|80
ICD9 = ICD9|703.8 ICD9|757.5
ICDO =
OMIM =
MedlinePlus =
eMedicineSubj = derm
eMedicineTopic = 812
MeshID = D009264

Pachyonychia congenita, also called simply pachyonychia, is an autosomal dominant skin disorder.

ymptoms

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

Pathophysiology

The condition is caused by genetic mutations in one of four genes that encode keratin proteins specific to the epithelial tissues affected in the two forms of the disorder. PC1 is caused by mutations in keratin 6A (protein name K6A; gene name "KRT6A") or keratin 16 (protein K16; gene "KRT16"). The PC2 form is due to mutations in the genes encoding keratin 6B (protein name K6B; gene name "KRT6B") or keratin 17 (protein K17; gene "KRT17"). Three of the genes causing PC were identified in 1995 [cite journal |author=McLean WH, Rugg EL, Lunny DP, "et al" |title=Keratin 16 and keratin 17 mutations cause pachyonychia congenita |journal=Nat. Genet. |volume=9 |issue=3 |pages=273–8 |year=1995 |pmid=7539673 |doi=10.1038/ng0395-273 |url=] [cite journal |author=Bowden PE, Haley JL, Kansky A, Rothnagel JA, Jones DO, Turner RJ |title=Mutation of a type II keratin gene (K6a) in pachyonychia congenita |journal=Nat. Genet. |volume=10 |issue=3 |pages=363–5 |year=1995 |pmid=7545493 |doi=10.1038/ng0795-363 |url=] with the fourth gene following in 1998. [cite journal |author=Smith FJ, Jonkman MF, van Goor H, "et al" |title=A mutation in human keratin K6b produces a phenocopy of the K17 disorder pachyonychia congenita type 2 |journal=Hum. Mol. Genet. |volume=7 |issue=7 |pages=1143–8 |year=1998 |pmid=9618173 |doi= |url=http://hmg.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=9618173]

Inheritance

Pachyonychia congenita follows an autosomal dominant pattern of inheritance, which means the defective gene is located on an autosome, and only one copy of the gene is required to inherit the disorder from a parent who has the disorder. On average, 50% of the offspring of an affected person will inherit the disorder, regardless of gender.

Occasionally, however, a solitary case can emerge in a family with no prior history of the disorder due to the occurrence of a new mutation (often referred to as a sporadic or spontaneous mutation).

Patient support

A patient support group exists for helping individuals affected by PC, called "PC Project". They actively seek PC patients, offer help and support, arrange genetic testing to confirm the diagnosis of PC, organize meetings for patients and researchers, and sponsor research into developing new treatments for the condition. A wealth of information on all aspects of PC can be found on their [http://www.pachyonychia.org/ website] .

References

External Links

*OMIM3|167200 RareDiseases|4188|Pachyonychia congenita type 1; Jadassohn Lewandowsky syndrome
*OMIM3|167210 RareDiseases|4188|Pachyonychia congenita Jackson Lawler type
*OMIM3|260130 RareDiseases|9436|Pachyonychia congenita recessive