The most common type of albinism is oculocutaneous albinism. This affects the skin, hair, and most importantly the eyes. The most severe cases causes these to turn white or pink, and also make the person have trouble seeing. There are two main causes of oculocutaneous albinism. These are:
Type 1: An amino acid, the building blocks of proteins in the body, called tyrosine is converted to another amino acid called melanin. However, if the enzyme that causes this to happen fails, then this will not occue.
Type 2: There is a defect in a gene. This only causes a slight problem in the pigmentation at birth.
There are several ways to diagnose albinism and carriers of albinism. One is merely obsevervation, noticing if the pigmentation is off. However, there is also a blood test now that determines carriers of albinism. Also, genetic testing is the most reliable, going through the genetics of the parents to determine if the offspring has it. Other ways include: an electroretinogram, chemical testing, and the tyrosinase test.
"Albinism-Diagnosis." Medindia.com. 28 Feb. 2009. Medina Health Network. 28 Feb. 2009
< http://www.medindia.com/patients/patientinfo/Albinism-Diagnosis.htm >.
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There are many types of albinism besides what is listed here. One of them is Hermansky-Pudlak Syndrome. You can't even make a guess about HPS based on looking at the affected person because the phenotype varies so widely. Genetic testing is not the gold standard either because not all the genes have been identified yet.
ReplyDeleteBut, the good news is a blood test can diagnose HPS. It's free - the only cost to the family is the blood draw and shipping of the blood.
It is important for children with albinism to be screened for HPS, even if no other genetic testing is done, because HPS involves progressive medical issues besides skin and vision.
For more info, go to: www.hpsnetwork.org.