If You Carry the XPC Mutation, What Are You at Risk For?
A mutation, or error, in the XPC gene is associated with xeroderma pigmentosum (XP), which is a rare inherited skin disorder characterized by extreme sun sensitivity. People with XP have a higher risk of developing skin cancer, often at a very early age. People who carry an XP mutation are also at risk for other cancers, including brain tumors and lung cancer. Researchers have found more than 40 mutations in the XPC gene that cause XP. Alterations in the XPC gene are the most common cause of XP in the United States, according to the American Society of Clinical Oncology. RELATED: Lower Risk, Greater Danger: What People of Color Need to Know About Skin Cancer
How Does XPC Increase Your Risk of Cancer?
Most XPC mutations halt the production of any XPC protein. When there’s a loss of this protein, cells can’t repair DNA damage normally. These DNA repair deficiencies cause people with XP to have an extreme sensitivity to UV rays. When UV rays damage genes, cells grow too quickly and in an uncontrolled way. Without repair genes at work, cells can rapidly turn cancerous. RELATED: A Parent’s Guide to Skin Cancer in Kids
Can You Be Tested for XPC?
Yes, you can be tested for an XPC mutation. Your doctor may recommend this test if XP is suspected or you have certain symptoms, risk factors, or a family history. You’ll provide a blood or saliva sample to be analyzed in a lab. You may want to talk with a genetic counselor before and after your test. This professional can help explain your results. RELATED: The Right Hat Can Help Prevent Skin Cancer
Why Is It Important to Know if You Are at Risk of XPC?
Knowing you have an XPC mutation can help you better understand the health risks you face. People with XP have almost a 100 percent risk of developing skin cancer if they don’t take careful precautions. You may also be able to share the information with family members who could be at risk too. XP is an autosomal recessive genetic disorder, which means it happens when a person inherits two copies of a gene for the same trait, one from each parent. If you inherit one normal gene and one defective gene for the disease, you’ll be considered a carrier but usually won’t show symptoms. The risk for two carrier parents to both pass the gene mutation and have an affected child is 25 percent with each pregnancy. RELATED: The Difference Between Chemical and Mineral Sunscreen
History of the XPC Gene: When Was It Discovered?
XP was first described by the dermatologist Moritz Kaposi in 1874. In 1968, James Cleaver, PhD, reported on defective DNA repair in cultured cells from people with XP. RELATED: AAD Guidelines Recommend Best Practices for Preventing and Treating Basal Cell and Squamous Cell Skin Cancer
What if You Test Positive for XPC?
If you test positive for an XPC mutation you can take certain measures to lower your risk of skin cancer or other problems. Your doctor might recommend:
Skin examinations every three to six monthsRegular eye examsRoutine neurologic evaluations
You’ll also need to take special care when you’re exposed to sunlight or some types of artificial indoor light. People with XP should cover their skin completely and wear UV-absorbing sunglasses when they’re outdoors.
