The skin is a complex organ made up of a number of tissue types, which work together to maintain the integrity of the skin and form a barrier between the environment and the rest of the body. Skin contains thousands of follicles, which contain populations of stem cells known as bulge cells. The skin is renewed as proliferating cells in the deep layers of the skin develop into mature skin cells as they grow towards the surface of the skin, then die and eventually get sloughed off. Layers of connective tissue, as well as oil glands known as sebaceous glands maintain the elasticity of the skin. Disruption of any tissue type within the skin can lead to the development of serious and potentially fatal disease. A number of genetic disorders affecting the skin have been identified.
Albinism
Albinism is a genetic condition that affects the skin, as well as other tissues like the hair and the iris of the eye. Patients with albinism do not make a protein called melanin, a pigment produced by cells called melanocytes, which gives color to the skin, hair and eyes. As the melanin is responsible for skin tone, it plays a role in protecting against UV radiation from the sun. These patients must be very mindful of sun exposure since they lack the skin's natural UV protection.
Patients with albinism carry genetic mutations that inactivate an enzyme responsible for part of melanin production. The genetic mutation can be autosomal dominant--meaning that one copy of a mutant gene results in albinism, or autosomal recessive--meaning that two copies of the gene must be mutated, according to the Texas School for the Blind and Visually Impaired.
Incontinentia Pigmenti
Incontinentia pigmenti is another genetic condition that affects the skin. Patients with incontinentia pigmenti experience skin blistering and spotting. The patients have uneven skin tone with patches of over-pigmented skin, which is caused by a buildup of melanin underneath the skin. In the majority of cases, incontinentia pigmenti is caused by genetic mutations on a region of DNA called the X chromosome, according to the University of Maryland Medical Center.
Since the disease is correlated with mutations to the X chromosome, it is called an X-linked trait. This affects males and females differently, since males have one X chromosome and females have two. When the genetic mutation occurs in males, their one copy of the gene is mutated, and the condition is often deadly. Cases of incontinentia pigmenti are more common in females, but the symptoms are generally less severe.
Xeroderma Pigmentosum
Xeroderma pigmentosum is a genetic disorder that increases the skin's sensitivity to the sun. Patients with xeroderma pigmentosum develop severe sunburns and abnormal pigmentation on areas of the skin exposed to sunlight. These patients are also at a very high risk for developing skin cancer, due to their sensitivity to the sun.
According to Ramapo College of New Jersey, xeroderma pigmentosum is an autosomal recessive disorder. This means that in order to have the disease, a patient must have both copies of the gene mutated. Parents may be a carrier for the disease, which means they have one copy of a mutant gene, but do not have the disease. If two carriers have a child, there is a 25 percent chance the child will have xeroderma pigmentosum.
