User:Anatomy244/sandbox/Albinism

Albinism _{Albinism refers to a range of disorders that are the result of reduction or absence of the pigment melanin.}

Melanin Melanin is the pigment that is produced from a melanocyte in the stratum basale layer of the epidermis. The epidermis is an integral part of the integumentary system. Melanocytes are not only located in the epidermis of the human body. These cells are also scattered in the ear, eye, and brain tissues. An individual with albinism contains the normal number of melanocytes in the stratum basale layer of the epidermis, but these melanocytes lack the required enzyme to produce melanin.

Role of Melanin

Melanin and the Skin Melanin shields the nuclear DNA of the keratinocyte when exposed to UV radiation and works to protect the skin against harmful UV sun exposure. It also plays a role in protecting the individual against skin cancer. Melanin determines skin pigment of the individual. There is an inverse relationship in regards to melanin and risk of skin cancer. The more melanin produced (darker skin), the lesser the risk for skin cancer, and vice versa.

Melanin and the Eye Melanin provides the pigment of the iris and plays a role in vision. An individual with albinism lacks pigment in the iris of the eye, a region of the eye that is responsible for eye color.The pigment in the iris, melanin, is responsible for absorbing light. Melanin in the eye is also responsible for tolerating bright light. An individual with albinism will be very sensitive to bright light, a condition known as photosensitivity, due to the lack of melanin in the iris. An individual with albinism may also have other vision problems that are not necessarily associated with melanin production. This can include an underdeveloped fovea, the part of the eye that is responsible for visual acuity. Visual acuity refers to sharpness, or clarity of vision.

Stimulation of Melanin Production Exposure to UV light will stimulate the production of melanin, as melanin is used to protect a keratinocyte’s (in the stratum basale) nuclear DNA from UV exposure. There are also many specific genes such as MC1R and others that play a role in what type of melanin the body produces.

Albinism

Albinism refers to a range of disorders that are the result of reduction or absence of the pigment melanin. It affects the hair, eyes, skin and vision. It is a genetic condition. It is caused by mutations of one of several genes. The genes that are affected play various roles in the production of melanin by melanocytes in the skin and eyes. This mutation interferes with the enzyme tyrosinase which makes melanin form the amino acid, tyrosine. Albinism is genetically inherited in an autosomal recessive manner which means the individual must get faulty copies of genes from both the mother and the father. 1 in 70 people carry the genes associated with albinism.

Symptoms

All forms of albinism result in issues with the development and function of the eyes because melanin plays a vital role in the development of the retina and the optic nerve pathways from the eye to the brain. Other symptoms include: light pale skin, very white to brown hair, very light blue to brown eyes that may appear red, high sensitivity to sun exposure, and increased risk of developing skin cancer.

Standard Methods of Treatment

Albinism is a genetic disease, therefore there are no cures for the symptoms. However, current treatment for albinism minimizes the symptoms for albinism.

Albinism and the Eye

Treatment includes focusing on maintaining proper eye care and monitoring skin conditions. Annual opthamologist visits are necessary for protective sunglasses because of heightened sensitivity to UV rays and prescription eyeglasses are often needed. In some extreme cases surgery on the muscles of the eyes are needed to correct abnormal eye movements. Albinism itself has no treatment, but some conditions that people with albinism have are treatable. Other conditions related to be albinism are manageable. For example, strabismus can be treated with glasses or surgery. Glasses can also help improve vision and reduce light sensitivity. For children with low vision, low vision aids such as hand-held magnifiers can help. Glasses with small telescopes attached are helpful for older children and adults. These lenses can help with both close and distant vision.

Albinism and the Skin

Albinism causes little to no melanin to form, so people with albinism are very sensitive to light and sun exposure. This increases their risk for developing skin cancer and other sun-damage related complications. It is important for people with albinism to care for their skin, use proper precautions when allowing exposure to sun, and monitor any freckles or moles with their dermatologists. The treatment of protecting the eyes and skin from prolonged exposure to the sun has many benefits besides from treating the albinism symptoms. Unprotected sun exposure can be very harmful to an individual’s skin and eyes, so it’s important in general to protect against the sun. The only contraindication of this treatment is that the individual may not get the necessary vitamin D one needs from the sun. To counter this, it’s important to receive vitamin D in other forms, such as supplements.

Albinism and Peer Groups

Parents, students and teachers can work together to help a child with albinism. It's important to consider seating, lighting and optical aids in the classroom. These can make learning easier for a child with albinism. Peer support groups can help children and adults with albinism. These groups can help the individual to feel less isolated, learn positive attitudes and coping skills from others with low vision, and gather valuable resource information.

Future Areas of Research

In one current research, a team led by Brown University biologist discovered the ways in which a specific genetic mutation has lead to the lack of melanin production due to an underlying form of albinism. This research shows that the protein is necessary for the proper functioning of an ion channel on the melanosome organelles. And so they found that when the melanosomes lacks OCA2 or it contains OCA2 with albinism, the chloride flow does not occur and the melanosome fails to produce melanin. With this discovery, new ideas for treating albinism can now be inspired. In terms of a therapeutic point of view, this means that they now have a channel that’s a possible drug target. And another potential treatment could be to alter melanosome acisity to make up for the lack of the protein. A separate experiment was done in order to ensure that melanin itself was not responsible for the chloride current. And the results proved that it was not. The research points to the key mechanism that breaks down when it fails. They concluded that OCA2 contributes to a novel melanosome - specific anion current that modulates melanosomal pH for optimal tyrosinase activity required for melanogenesis. Overall, now that researchers have discovered in which ways the mutations specifically affect the ion channels, they are able to fully understand the albinism and how to restore current and melanin production. Future research will most likely to continue building from these findings while also trying to discover new useful therapies that will advance the treatments. Scientists have known for about 20 years that the condition is linked to mutations throughout the gene, but never understood how the mutations lead to a melanin deficit. With this new information, they have the ability to create new ideas that would treat albinism. Considering about 1 in 40,000 people worldwide have type 2 oculocutaneous albinism, further research that would include ways to treat these cases.

References

Brown University (2014). New research unlocks a mystery of albinism. Retrieved November 11,

     2019 from https://news.brown.edu/articles/2014/12/albinism.

Gupta, Mrinali Patel (n.d). Albinism and Low Vision. Retrieved November 7, 2019 from https://www.visionaware.org/info/your-eye-condition/guide-to-eye-conditions/albinism-6165/125.

National Organization for Albinism and Hypopigmentation (2018). Retrieved November 7, 2019

      from https://www.albinism.org/information-bulletin-what-is-albinism/.

Newman. Tim (2018). Everything You Need to Know About Albinism. Retrieved November 7,

      2019 from https://www.medicalnewstoday.com/articles/245861.php.

Mayo Clinic (n.d). Albinism. Retrieved November 5, 2019 from

     https://www.mayoclinic.org/diseases-conditions/albinism/diagnosis-treatment/drc-20369189.

Porter, Daniel (n.d). Albinism Diagnosis. Retrieved November 5, 2019 from

    https://www.aao.org/eye-health/diseases/albinism-diagnosis.

U.S. Department of Health and Human Services (2016). Albinism. Retrieved November 7,

     2019 from https://rarediseases.info.nih.gov/diseases/5768/albinism. 

University of Chicago Medical Center (2005). Studies Shed Light On Role of Melanin In

     Preventing Macular Degeneration. Retrieved November 7, 2019 from 
     https://www.sciencedaily.com/releases/2005/07/050729062519.htm. 

Yamaguchi, Yuji & Hearing, Vincent J (2014). Melanocytes and Their Diseases. Retrieved

    November 7, 2019 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3996377/.

Pictures: https://openstax.org/books/anatomy-and-physiology/pages/1-introduction https://www.flickr.com/photos/enduroafrica/320532838/ Karen Grønskov, Jakob Ek, and Karen Brondum-Nielsen: Oculocutaneous albinism Orphanet J Rare Dis. 2007; 2: 43. doi: 10.1186/1750-1172-2-43. https://commons.wikimedia.org/wiki/File:Clip-on_sunglasses.jpg#/media/File:Clip-on_sunglasses.jpg