Your skin is affected by numerous external factors, such as your environment or your skin care routine. Underneath the surface, your skin is affected by a more permanent factor: your genes.
In general, genes, which are made of DNA, determine all the different characteristics of a living thing. They do this by telling your cells how to make proteins, which in turn affects all the structures and functions in your body. Scientists estimate that humans have between 20,000 and 25,000 different genes [source: Genetics Home Reference].
Genetics are complicated by the fact that there is no specific skin gene -- many genes work together to affect a single trait, and many traits can be affected by a single gene. Genes have a significant influence on skin because skin is made of so many proteins. For example, collagen, which forms the basic structure of your skin and gives it strength, is a protein. So is melanin, which is the pigment that gives your skin its color.
Often, genetic factors are thought of in terms of heredity -- that is, if your parents have a certain trait, you're likely to have it. This is at least partially true for many skin-related characteristics, such as skin type and skin color. However, it's not easy to definitively isolate genes that cause skin color. Many researchers have tried to determine which specific genes are linked to skin color and skin type, but more studies still need to be done because so many factors, both genetic and environmental, affect these traits [source: Barsh, Matulef].
So you now know that genes affect the normal characteristics of your skin, but what happens when genes behave in abnormal ways? Read on to find out how genetic disorders can affect the skin.
Genetic Skin Disorders
You can't have a gene for a certain disorder. Genetic disorders are caused by the mutation of a regular gene, which keeps it from giving instructions to proteins properly -- or at all [source: Genetics Home Reference: Mutations]. Another common myth about genetic disorders is that they are all congenital, or present at birth. In fact, you can get genetic disorders as your cells get older or if they're exposed to harmful chemicals. Of course, they can also be passed down from one generation to the next, and sometimes can be caused by a combination of both inheritance and environment [source: Mayo Clinic].
This is true of one common skin disorder: skin cancer. The most common risk factors for skin cancer include a variety of environmental and genetic factors, such as excessive sun exposure, living close to the equator, having light skin and freckles and having a family history of skin cancer [source: WebMD]. So how is genetics involved? Normally, your genes control your body's process of generating new skin cells to replace the older, dead cells. However, if the DNA is mutated, it sends incorrect instructions to skin cells, causing new cells to grow unchecked into a cancerous mass [source: Mayo Clinic].
Other genetic skin disorders are caused mostly or entirely by inherited factors include:
- Albinism causes the body to produce not enough melanin -- or none at all -- often resulting in very pale skin, hair and eyes, as well as vision problems [source: Mayo Clinic].
- Epidermolysis bullosa causes skin to be extremely fragile and susceptible to blisters [source: National Institute of Arthritis and Musculoskeletal and Skin Diseases].
- Ichthyosis causes the buildup of thick, dry, scaly skin [source: Mayo Clinic].
- Neurofibromatosis causes tumors under the skin and darker pigmented spots on the skin [source: Mayo Clinic].
There are dozens of other genetic disorders that affect the skin. But there are also many physicians and researchers who are dedicated to diagnosing, treating and understanding genetic skin conditions. To find out more about the genetic factors that affect your skin, follow the links on the next page.
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- Barsh, Gregory S. "What Controls Variation in Human Skin Color?" Public Library of Science. Oct. 13, 2003 (Accessed Oct. 7, 2009)http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=212702
- Columbia University Medical Center, Department of Neurological Surgery. "Phakomatoses." (Accessed Oct. 7, 2009)http://columbianeurosurgery.org/ct/phakomatoses.html
- Genetics Home Reference. "How can gene mutations affect health and development?" U.S. National Library of Medicine. Oct. 2, 2009 (Accessed Oct. 7, 2009)http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/mutationscausedisease
- Genetics Home Reference. "What is a gene?." U.S. National Library of Medicine. Oct. 23, 2009 (Accessed Oct. 27, 2009)http://ghr.nlm.nih.gov/handbook/basics/gene
- Genome News Network. "Genes." J. Craig Venter Institute. Jan. 15, 2003 (Accessed Oct. 7, 2009)http://www.genomenewsnetwork.org/resources/whats_a_genome/Chp1_3_2.shtml
- Matulef, Kim. "One fish, two fish, red fish, blue fish: What the colors of fish have taught us about human skin color." Stanford University Department of Genetics. (Accessed Oct. 7, 2009)http://www.thetech.org/genetics/news.php?id=27
- Mayo Clinic. "Albinism." April 4, 2009 (Accessed Oct. 7, 2009)http://www.mayoclinic.com/health/albinism/DS00941
- Mayo Clinic. "How genetic disorders are inherited." May 9, 2009. (Accessed Oct. 7, 2009)http://www.mayoclinic.com/health/genetic-disorders/DS00549
- Mayo Clinic. "Ichthyosis vulgaris." May 10, 2008. (Accessed Oct. 7, 2009)http://www.mayoclinic.com/health/ichthyosis-vulgaris/DS00734
- Mayo Clinic. "Neurofibromatosis Type 1." (Accessed Oct. 7, 2009)http://www.mayoclinic.org/neurofibromatosis-nf1/
- Mayo Clinic. "Skin Cancer." June 3, 2008. (Accessed Oct. 7, 2009)http://mayoclinic.com/health/skin-cancer/DS00190
- Merriam-Webster Medical Dictionary. "Collagen." (Accessed Oct. 7, 2009)http://www.merriam-webster.com/medical/collagen
- National Institute of Arthritis and Musculoskeletal and Skin Diseases. "Epidermolysis Bullosa." September 2009. (Accessed Oct. 7, 2009)http://www.niams.nih.gov/Health_Info/Epidermolysis_Bullosa/epidermolysis_bullosa_ff.asp
- WebMD. "Skin Cancer, Non Melanoma Guide -- What Increases Your Risk." Oct. 14, 2008. (Accessed Oct. 7, 2009)http://www.webmd.com/melanoma-skin-cancer/skin-cancer-guide/skin-cancer-nonmelanoma-what-increases-your-risk
- WebMD. "Psoriasis -- Cause." Dec. 10, 2007. (Accessed Oct. 7, 2009)http://www.webmd.com/skin-problems-and-treatments/psoriasis/psoriasis-cause
- WebMD. "Rosacea -- Topic Overview." July 24, 2007. (Accessed Oct. 7, 2009)http://www.webmd.com/skin-problems-and-treatments/tc/rosacea-topic-overview