Oculocutaneous Albinism Type One Paradise Valley High School October 25th, 2015 Introduction Melanin, the major pigment responsible for skin, hair, and eye coloration, is synthesized in cytoplasmic organelles called melanosomes. Melanosomes are the cellular site of synthesis, storage and transport of melanin pigments, and are found in melanocyte cells. Mutations in genes responsible for the necessary melanocyte proteins to make melanin pigment result in a reduction or absence of melanin pigment, a condition known as oculocutaneous albinism. Oculocutaneous albinism type one (OCA1) is a genetic deficiency associated with 0-10% of normal melanin production in the skin, hair, and eyes. They’re two subtypes of OCA1, OCA1A and OCA1B. Individuals …show more content…
Patients OCA1A have an absence of melanin, resulting in white hair, including eyelashes and eyebrows. The skin is also white unable to tan. OCA1A Patients develop Their irises are translucent and born light pink or red, but range in color from light blue to almost pink. These symptoms do not change over time, and don’t vary upon race. They have a visual acuity of 20/200 or less (20/20 being normal vision), and have intense photophobia. Patients with OCA1B are normally born with the same symptoms as those with OCA1A, but the hair and skin often develop some pigment over time. Their irises may change from blue to green/brown later in life. They often are born with visual acuity 20/100. There is also a type of OCA1b, known as temperature sensitive albinism, where there is white hair in the warmer areas of the body (such as scalp) and progressively darker hair in the cooler areas of the
It is “an inherited recessive condition in which the enzyme needed to synthesize melanin is nonfunctional, so melanocytes cannot produce melanin” (Human Anatomy Book, 124). Individuals with albinism “are more sensitive to sun exposure and have an increased risk of skin cancer” (medicalnewstoday.com). There are a variety of changes with people who have albinism, such as the skin tone, hair color, eye color, and the affected vision. The skin is typically pale, the hair is white, and the irises of the eyes may be pink (Human Anatomy Book, 124). With regards to the skin, individuals with albinism may “develop freckles” when they are exposed to the sun, since they are sensitive to the sunlight (medicalnewstoday.com). Furthermore, the vision of the individual may be affected in that the “eyes may not function in unison” and there may be a “lazy eye” involved (medicalnewstoday.com). Also, albinism is related to symptoms such as “crossed eyes, rapid eye movements, and light sensitivity” (medlineplus.gov). There are no cures to albinism, yet; there are only
The MCR1 gene provides instructions for making a protein called melanocortin 1 receptor. This receptor plays a major role when it comes to pigmentation. This receptor is located on cells that produce melanin called melanocytes. (https://ghr.nlm.nih.gov/gene/MC1R). Melanin is a substance that gives skin, hair, and eyes the color. Melanin is also found in the retina part of the eye, and it gives humans normal vision. Common variations (polymorphisms) in the MC1R gene are associated with normal differences in skin and hair color. Certain genetic variations are most common in people with red hair, fair skin, freckles, and an increased sensitivity to sun exposure. These MC1R polymorphisms reduce the ability of the melanocortin 1 receptor to
Albinism is a group of disorders that occur when a person inherits various genes that cannot produce the pigment melanin, which is the main substance that gives a person’s skin, hair, and eye color. The disease is divided into two types, oculocutaneous albinism, OCA, and Ocular Albinism. OCA causes decreased pigment in the eyes, hair, and skin. There are 4 types of OCA that are differentiated depending on the type of genetic defect. Ocular albinism affects primarily the eyes, while the skin and hair show normal or near-normal coloration.
“Achromatopsia affects roughly 1 in 33,000 Americans.” (2) Achromatopsia is a condition in which a person loses partial or all of their ability to see color and can also be referred to as achromatism, rod monochromatism, or total color blindness. It is the result of a change in one of the following genes: CNGA3, CNGB3, GNAT2, PDE6C, or PDE6H. Achromatopsia is a disorder that affects the retina, which is the part of the eye that is sensitive to light and forms visual images. Inside the retina is two different types of light receptor cells, called rods and cones. These cells use a process called phototransduction to send visual signals from the eye to the brain. Mutations in any of the genes above disrupt the phototransduction process, affecting
The white (w) and garnet (g) genes are sex-linked—both located on the X chromosome. The white locus (location: 1-1.5) has many alleles and can be responsible for a large range of eye color phenotypes. An allele of white, wcf, results in reduced levels of red and brown pigment (Mackenziea, et al. 1999). This causes a darker eye color, similar to that of the Rust mutant. Mutations in garnet (location: 1-44.4) are characterized by reduced levels of two distinct components—pteridine and xanthommatin, which are red and brown pigments respectively (Lloyd et al.
The research group carried out a genome wide association to scan for sequence variants that influence hair color, eye color and skin color in the europeans. Pigmentation in humans is attributed to the number type and cellular distribution of melanosomes. When different number of melanosomes are produced, they cause the differences in the skin pigmentation. The experiment was done with a sample of people from Iceland and Holland. The results of this experiment showed how the samples were broadly similar despite the fact that icelanders have more red hair, freckles and green eyes. They carried out two scans for each eye color, hair color and skin pigmentation traits. There were two overlapping regions on the MC1R on chromosome 16 and one of them is near a strong candidate for a strong
Colorblindness is a fascinating vison defect that impacts every day lives of those with the condition. There are multiple types of colorblindness that an individual can have, starting with partial color blindness and ending with total color blindness. However, the condition most commonly is passed genetically, effecting primarily males. In this paper I will be exploring the types of colorblindness that travel through genes, and how they impact people with the condition.
A person with tetrachromacy has an additional cone. This fourth cone makes them sensitive to ultraviolet light.
The white mutation causes a change in the pigmentation of the ommatida, the repeating units that make up the compound eye
Eye colour is a polygenic trait, meaning that the phenotype of the trait is one which is influenced by more than one gene. There are two genes which control the eye colours we are born with, which are obtained from our parents. The first gene, which is found in chromosome 15, is called EYCL3 and is responsible for brown or blue eye coloration. The second, which is found on chromosome 19, is responsible for green or blue eye colouring and is called EYCL1. It is currently unknown if other genes may determine the pigmentation of the iris in regard to patterns and placement, for example the difference between an eye of a single colour block, such as brown, instead of rays of different colours like hazel. (composed partially of green and brown)
Albinism is a recessive inherited defect in melanin metabolism in which pigment is absent from the hair, skin, and eyes (oculocutaneous albinism) or just from the eyes (ocular Albinism). Albinos tend to be children of parents who were first cousins.
Small lentigines ≤ 5 mm well defined, brown to black in color and could be widely distributed
Abetalipoproteinemia (ABL) is a rare inherited disorder affecting fat metabolism. Abnormal fat metabolism prevents the body from completely absorbing dietary fats, cholesterol, and fat-soluble vitamins. Without treatment, people affected by this disorder can experience progressive neurological deterioration, muscle weakness, difficulty walking, and blood abnormalities in which the red blood cells deform resulting in low levels of circulating red blood cells (anemia). Dietary fats and vitamins are essential for proper growth and development of various body systems. Consequently, degeneration of the retina of the eyes may also occur in affected people. This can potentially result in loss of vision, a condition known as retinitis pigmentosa.
Symptoms of Albinism vary from person to person. Many people think albino and picture pure white hair, the palest skin, and red eyes, but it really depends on the amount of pigment each person has. The skin of a person with the albino mutation is usually paler than most. This causes people with the mutation to be at a higher risk for skin cancers, and they can get sun damage easier than others. It is very important to stay protected out in the sun if a person is albino. For some people with the mutation they can start to produce melanin in their childhood and teen years which can cause a slight change in the
The current work revealed a significant association between the epidermal nucleo-cytoplasmic expression of LXR-α and absence of melanin pigment (P=0.001). This can be explained by Lee et al observation that LXR activation inhibited melanogenesis through the acceleration of extracellular signal–regulated kinase (ERK) mediated microphthalmia-associated transcription factor (MITF) degradation.6