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What are the

causes ofalbinism?

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Resume

Albinism is a defect of melanin production that results in little

or no color (pigment) in the skin, hair, and eyes. Occurs whenone of several genetic defects makes the body unable toproduce or distribute melanin, a natural substance that givescolor to your hair, skin, and iris of the eye.

The defects may be passed down through families.

The most severe form of albinism is called oculocutaneous

albinism. People with this type of albinism have white or pink

hair, skin, and iris color, as well as vision problems.

Albinism does not usually affect lifespan. Hermansky-Pudlaksyndrome can, however, shorten lifespan due to lung diseaseor bleeding problems.

People with albinism may be limited in their activities becausethey can't tolerate the sun.

Albinism is a genetic disorder caused by deficiency of

tyrosine, since the defect is based on an autosomal recessive,autosomal dominant, X-linked or a spontaneous mutation of

the enzyme, in some cases are not aware of specific gene

Alternatives names are oculocutaneous albinism; Ocular

albinism; Hermansky-Pudlak syndrome

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Table of Contents

Gratefulness .............................................................3

Thank our biology teacher for motivating and guiding

us in this project developed.....................................3

Gratefulness

Thank our biology teacher for motivating and guiding us in

this project developed

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Introduction

Albinism is a genetic disease responsible for the partial or

complete loss of pigmentation, that is to say, skin color, eyes or

hair. It is caused by mutations affecting the melanocytes, the

melanin pigment-producing cells that color these body parts. In

individuals with albinism, certain genetic alterations in

melanocytes prevent the synthesis of pigment or hinder their

distribution to the keratinocytes, the main type of cells in the

epidermis.

Common forms of albinism oculocutneas correspond to variants

of type 1 (OCA1) and type 2 (OCA2). OCA1 sufferers experience

TYR gene mutations responsible for the production of tyrosinase,

an enzyme used by cells to convert tyrosine, an amino acid in

pigment. OCA2, which is the most common variant in Africa,

resulting from a mutation in the OCA2 gene that encodes the P

protein, a protein whose role is not just decoded. It is likely thatthis mutation is the oldest among the causes of albinism, it is

believed, originated during the development of humanity in Africa.

Almost all have OCA1 albino white skin, white hair and eyes

without pigmentation. The iris, the colored circular region that

surrounds the pupil, is colorless, and the pupil, red. This redness is

caused by the reflection of light in the blood vessels of the retina,

the light-sensitive coating that lines the inside of the back of the

eye. Normally the pupils are black because the molecular pigments

absorb light in the retina and prevent glare and go outside. Those

with OCA2 may produce a small amount of pigment and therefore

less pronounced eye symptoms.

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General purpose

Find the underlying causes of albinism

Specific objectives

Find that mutation causes albinism

Study the types of albinism exist

Find treatments that are used for this disease

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Theoretical framework

Albinism is a genetic disorder mainly due to deficiency of tyrosine,

from the standpoint of genetic disease based on defects is

autosomal recessive, autosomal dominant, X-linked or a

spontaneous mutation of the enzyme, in some cases not aware of

the specific gene. Abin sufferers experience TYR gene mutations

responsible for the production of tyrosinase, an enzyme used by

cells to convert tyrosine, an amino acid in pigment. OCA2, which is

the most common variant in Africa, resulting from a mutation in

the OCA2 gene that encodes the P protein, a protein whose role is

not just decoded. It is likely that this mutation is the oldest among

the causes of albinism

Tyrosinase encodes tyrosine, carries genetic information from one

of the main enzymes responsible for the first step in the pathway

of melanin synthesis; to be a shortfall in tyrosinase in melanocytes

can not develop its stages which prevents melanin maturation

occurs and reacting to stimulation of the sun.

The melanocyte is a dendritic cell derived from neural crest and

migrate to the epidermis and hair follicles during embryogenesis.

Its main function is the production of melanin which is important

cosmetic and sunscreen. In the melanocyte, tyrosinase synthesis

of the complex and the formation of melanosomes is a parallel

process that begins in the rough endoplasmic reticulum (RER).

Tyrosinase passes the Golgi apparatus where it is activated by the

presence of copper. Once activated cytoplasmic vesicles is who will

join the melanosomes, which are based in turn on the RER as

autonomous and once premelanosomes melanosomes are Level I

and evolved into Level II melanosomes, which by being associated

with cytoplasmic vesicles containing tyrosinase activated give rise

to the level III melanosomes in which they will proceed to the

synthesis of melanin. The melanosomes reach the level IV and lose

their tyrosinase activity.

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Tyrosinase coenzyme situations have normal melanocytes at the

epidermal basal layer and contact with keratinocytes via their

dendrites, it is estimated that there is a melanocyte for every 36-

40 keratinocytes (epidermal melanin unit) or one melanocyte for

every 9 basal cells.

Classification of Albinism

Albinism can be classified into several types as follows:

Cutaneous or also called piebaldism

It is the least common, is inherited as an autosomal dominant.

People are characterized by skin and partially or completely

depigmented hair, eyes without pigment deficiency in the iris and

in some cases visually impaired.

Eye-AO

It is inherited by alterations or mutations in a gene on the X

chromosome or genes involved which are not known with

accuracy.

The people are characterized by decreased pigment in the eyes, is

sometimes accompanied by a slight deficit in the skin pigment and

hair, deficient visual acuity, nystagmus (eye tremor side),photosensitivity, in some cases, partial blindness total and

strabismus (deviation of one eye over the other or both).

AOC-cutaneous Oculus

Albinism is the most common and is divided into four types but

retain in these four cases, the discoloration of eyes, hair and skin.

AOC1

Produced by mutations or alterations in the tyrosinase gene that is

located on chromosome 11, these defects are more common in

Caucasian (white European Indo), and are divided into: Negative: Mutations or alterations in the tyrosinase gene that

disrupts the production of pigment, that is, over time it does not

obscure their pigmentation in general.

Positive: Interrupts are a partial pigment production causes a

mild pigmentation over time.

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ACO2

Mutations or alterations in the "gen p" chromosome 15, is mainly

in black people of African origin.

ACO3

Associated with mutations or alterations in the gene for thetyrosine-related protein type 1.

ACO4

Mutations corresponds to the "gene MAPT, is the most common in

Japan.

People at risk of inheriting albinism are:

Children of parents who have albinism.

Children of parents, who do not have albinism, but carry the

altered genes that cause this disorder.

A positive family history for albinism in a sibling or other relative.

Puerto Rican ancestry (this significantly increases the risk of an

atypical form of albinism called Hermansky-Pudlak syndrome).

Albinism is rare. In the United States, about 1 in every 17,000

people in general has some form of albinism. All races are affected,

but the AO occurs predominantly in Caucasians and the AOC in

blacks. Most children with albinism are born to parents with normal

hair color and skin to their ethnicity.

There is no cure for albinism. There are treatments for the purposeof preventing or limiting symptoms. In some cases, specific

treatment is needed for certain symptoms.

Preventive Treatment

Preventive treatment may include:

Protect the skin:

The risks of skin cancer and sunburn can be reduced to avoid sun

exposure whenever possible.

Use a sun protection factor (SPF) of 15 or more. Cover as much skin as possible with clothing when exposed to

the sun with clothing or sunscreen.

Protect the eyes

Wear sunglasses with UV protection whenever exposed to the

sun.

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The Sunglasses (UV protected) may relieve photophobia.

Specific Treatment of Symptoms

Specific treatment of symptoms of albinism may include:

For eyes:

Eyeglasses, contact lenses and / or optical aids to help improvevision.

Surgery to correct certain eye problems, including strabismus or

ambliopata.

Visual aids (in the classroom) to help children with albinism.

For skin

In case of developing skin cancer: surgery of the affected party

before they develop metastases.

These treatments can be especially important in Africa. The World

Health Organization estimates that thousands of people live thereconcerned not have access to important medicines and preventive

care.

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Methodology

Date Activity

07-19-10 chose the theme

07-23-10 We did the theoretical

framework

07-24-10 We finished our work

Did a search on the internet about the mutation that causes

albinism as we believe that is a major issue.

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Discussion and analysis

Albinism is a genetic disorder caused by deficiency of tyrosine,

since the defect is based on an autosomal recessive, autosomal

dominant, X-linked or a spontaneous mutation of the enzyme, in

some cases are not aware of specific gene

Mutations have been found in the CHS1 (also called LYST) gene.

The primary defect in this disease is found in certain granules

normally present in skin cells and certain white blood cells.

There are two main types of albinism:

Type 1 albinism is caused by defects that affect production of

the pigment, melanin. Type 2 albinism is due to a defect in the "P" gene. People

with this type have slight coloring at birth.

The most severe form of albinism is called oculocutaneousalbinism. People with this type of albinism have white or pink hair,skin, and iris color, as well as vision problems.

Another type of albism, called ocular albinism type 1 (OA1), affectsonly the eyes. The person's skin and eye colors are usually in thenormal range. However, an eye exam will show that there is nocoloring in the back of the eye (retina).

Hermansky-Pudlak syndrome (HPS) is a form of albinism caused bya single gene. It can occur with a bleeding disorder, as well as withlung and bowel diseases.

A person with albinism will have one of the following symptoms:

Absence of color in the hair, skin, or iris of the eye Lighter-than-normal skin and hair Patchy, missing skin color

Many forms of albinism are associated with the followingsymptoms:

Crossed eyes Light sensitivity

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Rapid eye movements Vision problems, or functional blindness

The goal of treatment is to relieve symptoms. Treatment dependson the severity of the disorder.

Treatment involves protecting the skin and eyes from the sun:

Reduce sunburn risk by avoiding the sun, using sunscreen,and covering up completely with clothing when exposed tothe sun.

Sunscreen should have a high sun protection factor (SPF). Sunglasses (UV protected) may relieve light sensitivity.

Glasses are often prescribed to correct vision problems and eyeposition. Eye muscle surgery is sometimes recommended tocorrect abnormal eye movements.

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http://www.nlm.nih.gov/medlineplus/ency/article/003040.htmhttp://www.nlm.nih.gov/medlineplus/ency/article/003040.htm

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Conclusions

Learned about the consequences that carry the mutation of

genes in person. For example: albinism

Knowing the symptoms that occur with this disease and

how those affected can cope

we learn more about mutations that occur in humans and

how they affect our lives

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Bibliography

http://www.nlm.nih.gov/medlineplus/spanish/ency/article/0014

79.htm

http://healthlibrary.epnet.com/GetContent.aspx?token=c905f6c8-fb81-4c5f-9ac5-57abe8fde16b&chunkiid=104026.

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Annexes

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