Methodology for albinism Essay Example | Topics and Well Written Essays - 1000 words

Methodology for albinism - Essay Example The condition is defined as "a group of congenital heterogeneous disorders in which there is either complete or partial absence of pigment in the skin, hair and eyes because of the absence of or a defect in an enzyme involved in the production of melanin" (Park et al, 2011). The pattern of inheritance of albinism is variable. It can be X-linked, autosomal dominant or autosomal recessive. It is mainly autosomal recessive in oculocutaneous albinism (Park et al, 2012). Clinical presentation is at birth and depends on the type of oculocutaneous albinism. There are basically ten types of oculocutaneous albinism of which four are common and merit importance. They are oculocutaneous albinism: type 1A, type 1B, type 2, type 3 and Hermansky–Pudlak syndrome (Park et al, 2012). The methodology of oculocutaneous albinism is clearly understood. In this essay, the methodology of oculocutaneous albinism will be discussed. Methodology Albinism is a genetic disorder that is hereditary. Genetic disorders are those conditions in which alteration of a specific gene leads to abnormal enzyme or protein production, leading to clinical manifestations. The main pathogenesis in albinism is abnormal synthesis or distribution of melanin. Melanin is a pigment that is responsible for the coloration of eyes, skin and hair. It is a protein and is synthesized in melanocytes from tyrosine, an aminoacid. Melanocytes are present in the skin, hair bulbs and eyes. The synthesis takes place in specialized organelles known as melanosomes. The most important enzyme in the production of melanin is tyrosinase. This enzyme converts tyrosine to dopa. The gene for tyrosinase is located in the chromosome 11. Mutations in the locus concerned with tyrosinase enzyme can lead to defective or absent tyrosinase. This can result in complete or partial absence of pigmentation of the skin, hair and eye. This type of oculocutaneous albinism is type-1. When the defect lies in P-polypeptide, which is a transport er for melanosomal tyrosine, type-2 oculocutaneous albinism arises. Tyrosinase is present in this type. Its functioning is also normal. But, the transporter is defective leading to the disease. The P gene is in chromosome 15. Patients with type-2 oculocutaneous albinism have some pigmentation, but it is lighter. Epithelial pigmentation of the retinal pigment around the macula is necessary for normal foveal development. Dopa, derived from tyrosine is essential normal retinal development as it is a mitotic agent. Lack of dopa leads to foveal hypoplasia and this can lead to decreased visual activity. Eventually the optic nerve fibers decussate abnormally and this leads to strabismus and monocular vision. Transillumination defects due to depigmented iris result in photophobia (Wei et al, 2011). In type-1 A, the clinical presentation is obvious at birth and the baby is born with blue-grey irides, light pink colored skin, depigmented white hair and predominant red reflex (Wei et al, 2011) . As the infant grows more symptoms related to eyes become obvious. These include nystagmus, decreased vision, strabismus, monocular vision and poor stereopsis. The skin can never develop pigmented lesions even after prolonged exposure to sunligh