A little girl with Albinism( License: CCO-BY-SA 2.0 generic]:
Wikipedia Commons The common misconceptions surrounding this weird disorder has existed for centuries. In certain parts of the world, Africa precisely, people affected by this disorder have suffered persecution, brutality, and discrimination.
It is probably the least understood condition among st many others and has been associated with some myths.
Surfing the internet some days back I came across this article that read :-
" AFRICA"S ALBINOS, DON'T HIDE !!
The statement of young children showing that they have been bullied, taunted and some even killed for being different form their peers. This had me thinking, the fact that most of us barely understand what Albinism is, is what makes it difficult to get rid of the brutality committed against these individuals.
UNDERSTANDING ALBINISM
It's not a magical curse or a spell cast on the parents for any sin of any kind.
Albinism is a genetic condition.
It is a inherent birth condition that is characterized by the visible lack of color in the skin, eyes and hair of the affected individual due to the lack of the pigment that is associated with giving this color .
Melanin pigment( License: CCO-BY-SA 3.0 unported]:
Wikipedia Commons The human Melanin
The major determinant of skin color.
It is produced by a group of specialized cells known as the Melanocytes. These cells are found in the Melanosomes and stimulate the melanin production by increasing the production of intracellular nitric oxide.
Melanogenesis occurs in the Liver from a precursor amino acid called Tyrosine. The Tyrosine is gotten from the breakdown of Phenylalanine, an essential amino acid produced in the body. The action of Phenylalnine hydroxylase leads to the breakdown of phenylalanine to tyrosine. The resulting L- tyrosine s further oxidized to give L-dihyroxyphenylalanine commonly known as L-DOPA
The L-DOPA is oxidized to DOPAquinone by the action of tyrosinase enzyme within the melanosome of the melanocytes.
DOPAquinone is the precursor for both eumelanin and pheomelanin in two different pathways. Eumelanin formation occurs starting from the conversion of DOPAchrome to LeucoDOPAchrome. DOPAchrome is converted to 5,6-dihydroxyindole in the presence of DOPAchrome tautomerase and dihydroxyindole-2-carboxylic acid oxidase.The conversion of 5,6-dihydroxyindole to indole-5,6-quinone by tyrosinase gives Eumelanin.
In the absence of tyrosinase, some genes have proven to be effective in Melanogenesis. The TYRP1 AND TYRP2 found in Melanosomes.
Pheomelanin synthesis occurs from the condensation of amino acid cysteine and DOPAquinone to form Cysteinyl DOPA. The oxidative polymerization of Cysteinyl DOPA in the presence of 1,4-benzothiazinylalanine gives Pheomelanin.
MYTH: Albinism is as a result of inbreeding or incest.
SCIENCE: Albinism is as a result of mutation in genes that express Melanin and can also be as a result of deficiency of tyrosinase, the enzyme responsible for the synthesis of DOPAquinone in melanogenesis
The deficiency of Tyrosinase, a copper containing enzyme that controls Melanin production may caused by a mutation in one of the tyrosinase genes.
The first type of albinism Occulocutaneous albinism is associated with this mutation.The tyrosinase gene is responsible for making the enzyme tyrosinase in the human body. The TYRP1 and the TYRP2 leading to the absence or reduced activity of Melanin.
The mutations may occur in five different forms.Two which are deletions of nucleotide(336-337delCA and 678-680delAGG). and three are mutations of (G109R, P205T and H256Y).
The Occulcutaneous albinism is of four types:
OCA1/OCA2/OCA3/OCA4.
As explained above the OCA1 is a deficiency of the tyrosinase enzyme. There is complete absence of melanin leading to white hair, very plae skin and white eyes.
The OCA2 is as a result of a defect of the OCA2 gene leading to a reduced production of melanin. The resulting albino may have yellow, blond hair.
The OCA3 is a mutation of the TYRP1 gene. This gene stabilizes the catalytic activity of tyrosinase in melanogenesis and helps in metal ion and protein binding to the enzyme. When it mutates the result is a diminshed production of melanin. It is very common in The South African region as the victims have reddish-brown skin and reddish hair to.
Occular Albinism mainly affects the eyes, showing a characteristic retinal hypopigmentation( License: CCO-BY-SA 3.0 unported]:
Wikipedia Commons A defect in a tyrosine binding protein SLC45A2 that transports substances for normal functioning of melanocytes.
- The second form of albinism is the Occular Albinism. Commonly associated with mutations of a gene located on the X chromosome.
The alteration to the geneGPR143 is enough to cause Occular albinism. Individuals with this form of albinism may have retinal pigmentation and eye abnormalities normally associated with albinism. e.g photophobia, strabismus.
MYTH: Albinism can be transferred through skin or physical contact
SCIENCE: Albinism is solely a genetic disorder. That is, it can only be transferred from parents to offspring.
The social stigma associated to having a very bizarre skin color, hair color and eye color is one that should be corrected.
Albinism is not a sexually transmitted disease or air-borne disease. It also cannot be contacted through physical contact with an albino.
If not through physical contact or sex, how then is Albinism gotten ?
A genetic condition is simply one that is inherited from parent to offspring.
The OCA has autosomal recessive inheritance
If both parents are carriers of the same type of OCA, the offsprings would also have OCA
If one partner is related to a carrier of OCA, there is an increased chance that one of the children may have OCA.
If one of the parents is carrier of the OCA, there is a 0.5 percent risk factor of having children with the same gene dominant or recessive.
Considering that the OA is an X-linked recessive inheritance, It would be commonly associated with boys. Although it is still very possible for a female to have this albinism type.
An affected male will have daughters that are carriers of the OA , and although not affected they have a chance of having offspring's with Albinism.
MYTH: People with albinism cannot see during the day but only at night
SCIENCE: Yes, it is true that people with albinism have eye defects but that doesn't mean blindness during the day.
With the right aids, most of the eye abnormalities associated with this condition can be subdued in order to give them a normal chance at life.
Summary
Albino's have normal human features just like the rest of us. Just like the rest of us they feed, they breathe, eat. They are not sterile and do not posses magical powers that can cure HIV or other sexually transmitted diseases. Their body parts do not make us rich or famous.
They simply lack the color giving pigment Melanin, due to factors like mutations of genes encoding the enzyme necessary for melanin production and overall deficiency of the enzyme responsible for melanin production Tyrosinase.
Albino's do not vanish.
This is the most absurd of all the myths. Just like the rest of us humans, they die from diseases or simply aging.
References
MYTHS ABOUT ALBINISMRetrieved on May 23rd, 2018.
MELANIN BIOSYNTHESISRetrieved on May 23rd, 2018.
HOW ALBINISM IS TRANSMITTED FROM PARENTSRetrived on May 23rd, 2018.
ALBINISM TYPESRetrived on May 23rd, 2018.