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Familial pityriasis rubra pilaris
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Reviewed March 2013
What is familial pityriasis rubra pilaris?
Familial pityriasis rubra pilaris is a rare genetic condition that affects the skin. The name of the condition reflects its major features: The term "pityriasis" refers to scaling; "rubra" means redness; and "pilaris" suggests the involvement of hair follicles in this disorder. Affected individuals have a salmon-colored skin rash covered in fine scales. This rash occurs in patches all over the body, with distinct areas of unaffected skin between the patches. Affected individuals also develop bumps called follicular keratoses that occur around hair follicles. The skin on the palms of the hands and soles of the feet often becomes thick, hard, and callused, a condition known as palmoplantar keratoderma.
Researchers have distinguished six types of pityriasis rubra pilaris based on the features of the disorder and the age at which signs and symptoms appear. The familial form is usually considered part of type V, which is also known as the atypical juvenile type. People with familial pityriasis rubra pilaris typically have skin abnormalities from birth or early childhood, and these skin problems persist throughout life.
How common is familial pityriasis rubra pilaris?
Familial pityriasis rubra pilaris is a rare condition. Its incidence is unknown, although the familial form appears to be the least common type of pityriasis rubra pilaris.
What genes are related to familial pityriasis rubra pilaris?
In most cases of pityriasis rubra pilaris, the cause of the condition is unknown. However, mutations in the CARD14 gene have been found to cause the familial form of the disorder in a few affected families. The CARD14 gene provides instructions for making a protein that turns on (activates) a group of interacting proteins known as nuclear factor-kappa-B (NF-κB). NF-κB regulates the activity of multiple genes, including genes that control the body's immune responses and inflammatory reactions. It also protects cells from certain signals that would otherwise cause them to self-destruct (undergo apoptosis).
The CARD14 protein is found in many of the body's tissues, but it is particularly abundant in the skin. NF-κB signaling appears to play an important role in regulating inflammation in the skin. Mutations in the CARD14 gene lead to overactivation of NF-κB signaling, which triggers an abnormal inflammatory response. Researchers are working to determine how these changes lead to the specific features of familial pityriasis rubra pilaris.
Read more about the CARD14 gene.
How do people inherit familial pityriasis rubra pilaris?
Familial pityriasis rubra pilaris usually has an autosomal dominant inheritance pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Affected individuals usually inherit the condition from one affected parent. However, the condition is said to have incomplete penetrance because not everyone who inherits the altered gene from a parent develops the condition's characteristic skin abnormalities.
The other types of pityriasis rubra pilaris are sporadic, which means they occur in people with no history of the disorder in their family.
Where can I find information about diagnosis or management of familial pityriasis rubra pilaris?
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about familial pityriasis rubra pilaris?
You may find the following resources about familial pityriasis rubra pilaris helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for familial pityriasis rubra pilaris?
What if I still have specific questions about familial pityriasis rubra pilaris?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding familial pityriasis rubra pilaris?
apoptosis ; atypical ; autosomal ; autosomal dominant ; cell ; familial ; gene ; ichthyosis ; incidence ; inflammation ; inherit ; inheritance ; inheritance pattern ; juvenile ; keratoderma ; palmoplantar keratoderma ; penetrance ; protein ; psoriasis ; sporadic
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (6 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.