Albinism is the congenital absence of pigment or coloration in a person, animal or plant resulting in white hair, feathers, cuticles, pink or blue eyes and scales. Albinism affects all living things including reptiles, people, plants and birds. In animals, the scales, cuticles, feathers and the skin are white and the eyes are either pink or blue. In plants and algae, albinism is characterized by complete or partial loss of chlorophyll pigments and incomplete differentiation of chloroplast membranes. Albinism in plants usually interferes with photosynthesis which can reduce survivability. For today, let’s focus on humans.

The cause of albinism is a defect in 1 of the several genes that produce or distribute melanin, the pigment that gives skin, eyes and hair their color. Children are likely to be born with Albinism if both of their parents have albinism or both of their parents carry the gene of albinism. Most people with albinism have parents who are only carriers of the gene and don’t have symptoms.

Different gene defects characterize the numerous types of Albinism, listed below;

OCULACUTANEOUS ALBINISM (OCA)

This affects the skin, hair and eyes, further classified into;

OCA1, caused by a defect in tyrosinase enzyme, that results in white hair and skin at birth and white irises that don’t become darker over time.

OCA2, less severe than OCA1. It is caused by a defect in the OCA2 gene that results in reduced melanin production. People with OCA2 are born with light coloring around their skin. Their hair maybe yellow, blonde or light brown.

OCA3, is a result of a defect in the TYRP gene. It usually affects people with dark skin particularly black people in southern Africa. These people usually have reddish-brown skin, reddish hair and hazel or brown eyes.

OCA4 caused by a defect in the SLC45A2 protein. It results in the minimal production of melanin and commonly appears in people of East Asia decent.

OCULAR ALBINISM

This usually occurs as a result in mutation on the X-chromosome and occurs almost exclusively in males. People with ocular albinism have reduced coloring in the retina and Iris. The condition does not affect the skin or hair.

HERMANSKY-PUDLAK SYNDROME

A rare autosomal recessive disorder characterized by OCA, a bleeding diathesis and other organ involvement specific to certain types. The syndrome occurs with lung, bowel and bleeding disorders.

CHEDIAK-HIGASHI SYNDROME

The skin usually is creamy white or grayish. Hair is usually brown or blonde with a silvery sheen. People with this syndrome have a defect in white blood cells, increasing their risk of recurrent bacterial and pyogenic infections. They also present with progressive neurological abnormalities and mild risk of coagulation defects.

GRISCELLI SYNDROME

Characterized by hypopigmentation of the hair (grey) that doesn’t affect the entire body with immunodeficiency which leads to death in early childhood.

 



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