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Diseases

Genetic and Rare Diseases Information Center (GARD)

Pachyonychia congenita


Other Names for this Disease
  • Congenital pachyonychia
  • Pachyonychia congenita syndrome
Related Diseases
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Your Question

How many types of pachyonychia congenita are there? How are they caused? How many individuals have this condition and what is the mortality rate?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

Are there different types of pachyonychia congenita?

There are five different types of pachyonychia congenita, which are classified based on the specific keratin gene involved: KRT6A, KRT6B, KRT6C, KRT16, and KRT17. The age of onset and associated symptoms vary depending on which gene is affected and the exact mutation.[1][2]
Last updated: 12/10/2015

What causes pachyonychia congenita?

Pachyonychia congenita (PC) is caused by changes (mutations) in one of five genes: KRT6A, KRT6B, KRT6C, KRT16, and KRT17. These genes provide instructions for making a protein called keratin, which is found in the skin, hair, and nails. Mutations in any of these genes alter the structure of keratin proteins which interferes with their ability to provide strength and resilience to various parts of the body. This leads to the many signs and symptoms associated with pachyonychia congenita.[3]

PC is divided into 5 types based on the specific keratin gene involved: PC-K6a, PC-K6b, PC-K6c, PC-K16, and PC-K17.[2]
Last updated: 12/10/2015

How is pachyonychia congenita inherited?

Pachyonychia congenita (PC) is inherited in an autosomal dominant manner.[2][3] This means that to be affected, a person only needs a change (mutation) in one copy of the responsible gene in each cell. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new (de novo) mutations in the gene. These cases occur in people with no history of the disorder in their family. A person with PC has a 50% chance with each pregnancy of passing along the altered gene to his or her child.
Last updated: 12/10/2015

How common is pachyonychia congenita?

Although it is unclear exactly how many people are affected by pachyonychia congenita (PC), it appears to be rare.[4][3]

The Pachyonychia Congenita Project coordinates the International PC Research Registry to gather information on people diagnosed with this condition and support research. To date, the International PC Research Registry has identified 535 people with genetically confirmed PC. An additional 600 people with some features of PC have not yet undergone genetic testing.[1]
Last updated: 12/11/2015

What is the long-term outlook for people with pachyonychia congenita?

The long-term outlook (prognosis) for people with pachyonychia congenita (PC) varies. Although the condition is not associated with a reduced lifespan, it can negatively impact quality of life. Almost all affected people report constant pain caused by plantar keratosis (thickened skin on the soles of the feet) with underlying blisters and/or various types of cysts (i.e. steatocystoma and pilosebaceous cysts - two types of sebaceous gland cysts). This pain can interfere with mobility and day-to-day activities.[2][4]

For more information on living with PC, please visit the Pachyonychia Congenita Project's website.
Last updated: 12/11/2015

References
Other Names for this Disease
  • Congenital pachyonychia
  • Pachyonychia congenita syndrome
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.