Albinism pathophysiology: Difference between revisions
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* [[Mutation]] in [[Tyrosinase]] [[enzyme]] is responsible for causing [[albinism]] | * [[Mutation]] in [[Tyrosinase]] [[enzyme]] is responsible for causing [[albinism]] | ||
* [[Tyrosinase]] converts [[tyrosine]] to [[DOPA]] and then [[dopaquinone]]; subsequenstly, [[dopaquionone]] converts to either [[eumelanin]] or [[pheomelanin]] | * [[Tyrosinase]] converts [[tyrosine]] to [[DOPA]] and then [[dopaquinone]]; subsequenstly, [[dopaquionone]] converts to either [[eumelanin]] or [[pheomelanin]] | ||
* [[Tyrosinase]] mutation is seen in [[oculocutaneous albinism]] 1 ([[OCA1]]) and [[autosomal-recessive ocular albinism]] ([[AROA]]) | * [[Tyrosinase]] mutation is seen in [[oculocutaneous albinism]] 1 ([[OCA1]]) and [[autosomal-recessive]] [[ocular albinism]] ([[AROA]]) | ||
==References== | ==References== | ||
Revision as of 01:54, 18 August 2021
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Albinism Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Albinism pathophysiology On the Web |
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American Roentgen Ray Society Images of Albinism pathophysiology |
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Risk calculators and risk factors for Albinism pathophysiology |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Shadan Mehraban, M.D.[2]
Overview
Pathophysiology
Physiology
- Melanocytes are derived from neural crest ectoderm and are found in hair follicles, skin, eyes, and inner ear
- Melanocytes account for 5% to 10% of cells in epidermal basal layers
- Melanocytes contain melanosomes which produce melanin
- Melanin protects skin from ultraviolet; with sun exposure melanin pigment increases in the skin
- Apart from the photo-protective effect of melanin, it has some roles in the development of ocular structures as well as oculoneural pathways
- Melanin converts tyrosine to 2 forms named eumelanin and pheomelanin
- Eumelanin is responsible for black or brown skin color and protects skin from ultraviolet B
- Pheomelanin is responsible for red or blond hair and light-colored, and ruddy skin
- On melanocytes, activation of melanocortin one receptors (MC1R) lead to synthesis of eumelanin over pheomelanin
Pathogenesis
- Mutation in Tyrosinase enzyme is responsible for causing albinism
- Tyrosinase converts tyrosine to DOPA and then dopaquinone; subsequenstly, dopaquionone converts to either eumelanin or pheomelanin
- Tyrosinase mutation is seen in oculocutaneous albinism 1 (OCA1) and autosomal-recessive ocular albinism (AROA)