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    Albinism (HPS)

    Albinisitic man portrait[1]

    Albinism (achromia, achromasia, achromatosis) is defined as a group of inherited disorders characterized by a deficit in the production of melanin with deficiency or absence of pigment in the skin, hair and eyes.

    The disorder is triggered by this process: congenital.

    Presentation

    The main sign of albinism is the lack of pigment in skin, eyes, and hair. Other symptoms include vision difficulties. Common signs and symptoms are [6]:

    • Pink skin. However, skin color can vary from white to a brown and may even be seen as a normal hue. Skin can also change in children and teens as melanin production increases during the teenage years.
    • The appearance of freckles or moles on exposed skin.
    • White hair. Patients of Asian or African descent might present yellow, red, or brown hair that may darken over the years.
    • Light blue to brown eyes and translucent irises. 
    • Nystagmus, photophobia, astigmatism, strabismus, or extreme farsightedness or nearsightedness can be seen.

    Entire body system
    Increased Susceptibility to Infections
    • This also affects essential granules present in immune cells leading to increased susceptibility to infection.[en.wikipedia.org]
    • This also affects essential granules present in immune cells leading to increased susceptibility to infection. [3] Albinism results from inheritance of recessive gene alleles and is known to affect all vertebrates , including humans .[en.m.wikipedia.org]
    Pain
    • Since eyes with albinism have insufficient pigment (melanin) to effectively absorb light, sunlight and brightly-lit environments may be uncomfortable and even painful and cause even more difficulty seeing.[ocutech.com]
    • It is painful and causes extreme sensitivity to light.[en.wikipedia.org]
    • The lenses can be tinted to ease pain from too much sunlight.[encyclopedia.com]
    • Glasses are usually needed and can be tinted to ease pain from too much sunlight.[medical-dictionary.thefreedictionary.com]
    • It is painful and causes extreme sensitivity to light. [11] Reduced visual acuity due to foveal hypoplasia and possibly light-induced retinal damage. [8] Eye conditions common in albinism include: Nystagmus , irregular rapid movement of the eyes back[en.m.wikipedia.org]
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  • neurologic
    Nystagmus
    • When the eyes turn away from the null point nystagmus often increases.[ocutech.com]
    • Nystagmus For nystagmus, eye muscle surgery can reduce the movement of the eyes.[patient.info]
    • Nystagmus is best described as involuntary, rhythmic eye movements.[lensshopper.com]
    • The lack of eye pigment causes photophobia (sensitivity to light), nystagmus, and decreased visual acuity.[medicinenet.com]
    • […] no nystagmus or strabismus.[genome.jp]
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  • Skin
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  • respiratoric
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  • musculoskeletal
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  • urogenital
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  • Eyes
    Photophobia
    Retinal Damage
    • Light-induced retinal damage has been postulated as a contributing mechanism to decreased visual acuity.[emedicine.medscape.com]
    • Many albino animals face a higher risk of melanomas and retinal damage.[mdc.mo.gov]
    • Reduced visual acuity due to foveal hypoplasia and possibly light-induced retinal damage.[en.wikipedia.org]
    • It is painful and causes extreme sensitivity to light. [11] Reduced visual acuity due to foveal hypoplasia and possibly light-induced retinal damage. [8] Eye conditions common in albinism include: Nystagmus , irregular rapid movement of the eyes back[en.m.wikipedia.org]
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  • Workup

    After a physical examination coupled with a description of pigmentation changes, and familial comparisons, albinism can usually be diagnosed [7]. The physical exam will also be paired with an eye exam. A genetic test is necessary in order to confirm albinism and detect which specific subtype of the condition is present. 

    Laboratory

    Serum
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  • Treatment

    There is no cure for albinism, only management measures that a patient is recommended to follow [9]. A patient experiencing vision problems may be prescribed glasses, bifocals, or other vision aids. If a patient is experiencing strabismus, eye patches, especially for infants, or surgery might be beneficial. Tinted glasses may be used to improve photophobia

    Other recommendations concern the protection of the patient’s sensitive skin. Wearing a hat while in the sun, using sunblock on exposed skin, or wearing long sleeves and pants is recommended. 

    Prognosis

    While albinism has no effect on a patient’s lifespan, it can limit their activities. Due to the sensitive nature of the skin, daily activities in normal sunlight might prove to be difficult without some layer of protection. Sunlight or other bright lights might affect vision due to the eyes’ sensitivity.

    Complications

    Congenital Deafness
    • View Article PubMed Google Scholar Waardenburg PJ: A new syndrome combining developmental anomalies of the eyelids, eyebrows and nose root with pigmentary defects of the iris and head hair and with congenital deafness.[ojrd.biomedcentral.com]
    Deafness
    • The ocular findings are typical but deafness is not significant until late midlife.[disorders.eyes.arizona.edu]
    • In some forms of ocular albinism, the hearing nerves hearing may be affected and the person may develop hearing problems or deafness over time.[teenshealth.org]
    • A syndrome of sensory deafness and partial albinism is referred to as the albinism-deafness syndrome or the Waardenburg syndrome [ 48 ].[ojrd.biomedcentral.com]
    • "A Syndrome of Deaf-Mutism Associated with Albinism Showing Dominant Autosomal Inheritance" .[en.m.wikipedia.org]
    • Waardenburg's syndrome (WS) [ 6 ] WS is characterised by pigmentary and ocular features with sensorineural deafness.[patient.info]
    Esotropia
    • Strabismus (misalignment of the eyes) It is very common in albinism to have strabismus– either an inward (Esotropia) our outward (Exotropia) turning of the eyes.[ocutech.com]
    • In the case of esotropia or “crossed eyes,” surgery may help vision by expanding the visual field (the area that the eyes can see while looking at one point).[albinismaustralia.org]
    Strabismus
    • Strabismus and visual inattention is also present in the first six months of life.[orpha.net]
    • Surgery may be required for strabismus.[medical-dictionary.thefreedictionary.com]
    • Strabismus (misalignment of the eyes) It is very common in albinism to have strabismus– either an inward (Esotropia) our outward (Exotropia) turning of the eyes.[ocutech.com]
    • Ocular involvement causes strabismus, nystagmus, and decreased vision.[merckmanuals.com]
    • Strabismus — A disorder in which the eyes do not point in the same direction.[encyclopedia.com]
    Vitiligo
    • […] hakuhishō ) Norwegian: albinisme (no) m Polish: albinizm (pl) m Portuguese: albinismo (pt) m Romanian: albinism (ro) n Russian: альбини́зм (ru) m ( alʹbinízm ) Spanish: albinismo (es) m Tagalog: pagkaanak-araw See also [ edit ] axanthism leucism melanism vitiligo[en.wiktionary.org]
    • A related disease is vitiligo , in which localized areas of the skin lack pigment and resemble that of an albino, while elsewhere on the body the pigmentation is normal.[britannica.com]
    • Compare piebald, vitiligo .[medical-dictionary.thefreedictionary.com]
    • "Biology and genetics of Oculocutaneous albinism and vitiligo-common pigmentation disorders in Southern Africa" .[en.m.wikipedia.org]
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  • Etiology

    • The cause of albinism type OCA 1 and AROA, lies in a defective enzyme called tyrosinase. This enzyme contains copper and is involved in the production of melanin and other pigments from tyrosine by oxidation [2]. The tyrosinase enzyme is encoded by the TYR gene with the gene location 11q14-21. 
    • Mutations in tyrosinase-related protein 1 (TRP1), coded on chromosome 9 cause OCA 3. 
    • Mutation to the P gene, enconding for P protein which plays a role in regulating the pH of melanosomes, causes OCA 2.

    Epidemiology

    Albinism can affect people from all ethnic backgrounds. According to reports, it occurs in about one person out of 17,000 people worldwide. A patient’s lifespan is not affected by albinism as there is no link between the condition and mortality [3]. In general, a person’s health will remain normal aside from the associated conditions. 

    Sex distribution
    Age distribution

    Pathophysiology

    A congenital hypopigmentation within the systemic and ocular tissues is present [4]. Cellular pigmentation relies on the individual cell’s capability to manufacture as well as isolate the melanin pigment. This process happens inside organelles known as melanosomes. These are found in the melanocyte cells of the iris’s stroma, the ciliary body, choroid pigments, the skin, the conjunctive of the eye, and the hair. Melanin is synthesised through tyrosine inside of the melanosome.

    Tyrosinase plays a dominant role in albinism and affected individuals are therefore classified as being tyrosinase-positive or tyrosinase-negative depending on the results of a hair bulb test or an electron microscopy of the skin or hair. In both cases, there is usually an autosomal recessive inheritance pattern detected. If a patient is found to be tyrosinase-negative, the enzyme is considered to be inactive. This stops the cell from using the enzyme in order to produce melanin pigment. In the opposite case, the activity level of the tyrosinase enzyme is actually normal, but the cell is unable to synthesize the melanin due to defects in other enzymes involved in the pathway.

    Prevention

    This is a genetic condition so prevention is not possible. If patients are concerned about passing down the trait to their children, they are able to seek genetic counselling for help [10].

    Summary

    Albinism is a group of inherited disorders characterized by a deficit in the production of melanin with deficiency or absence of pigment. The disorder is also known as achromia, achromatosis, or achromasia [1]. The condition is classified in two forms, ocular albinism (OA) and oculocutaneous albinism (OCA), which are divided into several subtypes based on the location of the genetic mutation, (OCA 1, OCA 2, OCA 3) and (OA1, AROA).

    Along with the loss of pigment, the condition can also be associated with vision problems including nystagmus, astigmatism, and photophobia. In relation to the skin, albinism is associated with various skin cancers and chronic sunburns.

    Patient Information

    Albinism is an inherited condition distinguishable by the absence of melanin pigment in the patient. This pigment is responsible for the color of a person’s hair, eyes, and skin. The condition is usually accompanied by a sensitivity to the sun and is linked to an increased risk of various skin problems including skin cancer. Vision problems are also associated with albinism.

    Albinism can affect people from all ethnic background. It is genetic and can’t be caused by outside influences.

    There is no cure for albinism, but there are a number of things that a person can do to manage the condition. Using protective layers including sunscreen and loose clothes is recommended to protect sensitive skin. Eyeglasses can be prescribed for vision problems and sunglasses are recommended when outdoors.

    Some people may also experience nonmedical issues due to their albinism. This can include social isolation and discrimination. These issues can be handled with the help of a therapist or other counsellor who can help a patient work through these social problems.

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    References

    1. Summers CG. Albinism: classification, clinical characteristics, and recent findings. Optom Vis Sci. Jun 2009;86(6):659-62. 
    2. Schiaffino MV, Tacchetti C. The ocular albinism type 1 (OA1) protein and the evidence for an intracellular signal transduction system involved in melanosome biogenesis. Pigment Cell Res. Aug 2005;18(4):227-33.
    3. Innamorati G, Piccirillo R, Bagnato P, Palmisano I, Schiaffino MV. The melanosomal/lysosomal protein OA1 has properties of a G protein-coupled receptor. Pigment Cell Res. Apr 2006;19(2):125-35.
    4. Wang T, Waters CT, Jakins T, et al. Temperature sensitive oculocutaneous albinism associated with missense changes in the tyrosinase gene. Br J Ophthalmol. Oct 2005;89(10):1383-4.
    5. Ramsay M, Colman MA, Stevens G, et al. The tyrosinase-positive oculocutaneous albinism locus maps to chromosome 15q11.2-q12. Am J Hum Genet. Oct 1992;51(4):879-84. 
    6. Kaplan J, De Domenico I, Ward DM. Chediak-Higashi syndrome. Current Opinion in Hematology 2008 15 (1): 22–29.
    7. Kruijt B et al. Ocular straylight in albinism. Optom Vis Sc 2011;88:E585-E592
    8. Carden SM, Boissy RE, Schoettker PJ, Good WV. Albinism: modern molecular diagnosis. The British Journal of Ophthalmology 1998 82 (2): 189–95.
    9. Gronskov K, Ek J, Brondum-Nielsen K (2 November 2007). "Oculocutaneous albinism". Orphanet Journal of Rare Diseases 2: 43.
    10. Lee J. Surgical management of nystagmus. Journal of the Royal Society of Medicine 2002 95 (5): 238–41.

    • Anomalies of the eyelids, eyebrows and noseroot with pigmentary anomalies of the iris and head hair and with congenital deafness; Dystopia canthi medialis et - PJ Waardenburg - American journal of human genetics, 1951 - ncbi.nlm.nih.gov
    • A novel interstitial deletion of KAL1 in a Japanese family with Kallmann syndrome - K Nagata, T Yamamoto, H Chikumi, T Ikeda - Journal of human , 2000 - Springer
    • A syndrome of deaf-mutism associated with albinism showing dominant autosomal inheritance - W Tietz - American journal of human genetics, 1963 - ncbi.nlm.nih.gov
    • X-CHROMOSOMAL TRANSMISSION. A FAMILY CLAN WITH FUNDUS ALBINISM, FOVEA HYPOPLASIA, NYSTAGMUS, MYOPIA, ASTIGMATISM AND - H Forsius, AW Eriksson - Klinische Monatsblatter fur , 1964 - ukpmc.ac.uk
    • Albinism - CJ Witkop - Clinics in Dermatology, 1989 - Elsevier
    • Albinism: classification, clinical characteristics, and recent findings - CG Summers - Optometry & Vision Science, 2009 - journals.lww.com
    • Albinism: modern molecular diagnosis - SM Carden, RE Boissy, PJ Schoettker - British journal of , 1998 - bjo.bmj.com
    • Albinism with haemorrhagic diathesis: Hermansky-Pudlak syndrome. - PE Kinnear, EG Tuddenham - British journal of ophthalmology, 1985 - bjo.bmj.com

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    1. Albinisitic man portrait, CC BY-SA 3.0

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