TAONG ENGKANTO (ALBINISM SYNDROME)

    I used to  have a friend who look so different from other children,his name was Peter .He was extremely white from head to toes and people would say he is a son of an "engkanto" . His mother was impregnated by a fairy ,in fact he's the only one different from the rest of his siblings.Sometimes his father would accused his mother of cheating on their marriage ,Though they lived together friction happens sometimes.For me I kind of believe it was true ,he is a son of engkanto,I was so young then.Until I saw on TV a documentary show about rare kids diseases.Pls .take your time to read,maybe you can help explain to others that has this disease you may encounter one day .

Albinism in humans

Albinism is a congenital disordercharacterized in humans by the complete or partial absence of pigment in the skin, hair and eyes. Albinism is associated with a number of vision defects, such asphotophobia, nystagmus, and amblyopia. Lack of skin pigmentation makes for more susceptibility to sunburn and skin cancers. In rare cases such as Chédiak–Higashi syndrome, albinism may be associated with deficiencies in the transportation of melanin granules. This also affects essential granules present in immune cells leading to increased susceptibility to infection.[4]

AlbinismSynonymsAchromia, achromasia, achromatosis

Genetics

Oculocutaneous albinism is generally the result of the biological inheritance ofgenetically recessive alleles (genes) passed from both parents of an individual for example OCA1 and OCA2. A mutation in the human TRP-1 gene may result in the deregulation of melanocyte tyrosinase enzymes, a change that is hypothesized to promote brown versus black melanin synthesis, resulting in a third oculocutaneous albinism (OCA) genotype, ″OCA3″.[15] Some rare forms are inherited from only one parent. There are other genetic mutations which are proven to be associated with albinism. All alterations, however, lead to changes in melanin production in the body.[10][16] Some of these are associated with increased risk of skin cancer (see list of such genetic variations).

The chance of offspring with albinism resulting from the pairing of an organism with albinism and one without albinism is low. However, because organisms (including humans) can be carriers of genes for albinism without exhibiting any traits, albinistic offspring can be produced by two non-albinistic parents. Albinism usually occurs with equal frequency in both sexes.[10]An exception to this is ocular albinism, which it is passed on to offspring through X-linked inheritance. Thus, ocular albinism occurs more frequently in males as they have a single X and Y chromosome, unlike females, whose genetics are characterized by two X chromosomes.[17]

There are two different forms of albinism: a partial lack of the melanin is known as hypomelanism, or hypomelanosis, and the total absence of melanin is known asamelanism or amelanosis.

Enzyme

The enzyme defect responsible for OCA1-type albinism is tyrosine 3-monooxygenase (tyrosinase), which synthesizes melanin from the amino acid tyrosine.

Evolutionary theories

It is suggested that the early hominin evolved in East Africa around 3 million years ago.[18]The dramatic phenotypic change fromprimate to early hominin is hypothesized to have involved the extreme loss of body hair – except for areas most exposed to UV radiation, such as the head – to allow for more efficient thermoregulation in the early hunter-gatherers. The skin that would have been exposed upon general body hair loss in these early hominins would have most likely been non-pigmented, reflecting the pale skin underlying the hair of our chimpanzee relatives. A positive advantage would have been conferred to early hominids inhabiting the African continent that were capable of producing darker skin – those who first expressed the eumelanin-producing MC1Rallele – which protected them from harmful epithelium-damaging ultraviolet rays. Over time, the advantage conferred to those with darker skin may have led to the prevalence of darker skin on the continent. The positive advantage, however, would have had to be strong enough so as to produce a significantly higher reproductive fitness in those who produced more melanin. The cause of a selective pressure strong enough to cause this shift is an area of much debate. Some hypotheses include the existence of significantly lower reproductive fitness in people with less melanin due to lethal skin cancer, lethal kidney disease due to excessvitamin D formation in the skin of people with less melanin, or simply natural selection due to mate preference and sexual selection.[18]

When comparing the prevalence of albinism in Africa to its prevalence in other parts of the world, such as Europe and the United States, the potential evolutionary effects of skin cancer as a selective force due to its effect on these populations may not be insignificant. The prevalence of albinism in some ethnic groups in sub-Saharan Africa is around 1 in 5,000, while in Europe and the US it is 1 in 20,000.[18] It would follow, then, that there would be stronger selective forces acting on albino populations in Africa than on albino populations in Europe and the US. Rates as high as 1 in 1,000 have been reported for some populations in Zimbabwe and other parts of Southern Africa.[19] In two separate studies in Nigeria, people with albinism were found to be of reproductively significant age more often than not. One study found that 89% of people diagnosed with albinism are between 0 and 30 years of age, while the other found that 77% of albinos were under the age of 20.[19]

Source : wikipedia
   
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       emerita gitgit
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