Albinism

The most common cause of albinism is a defect in tyrosinase, the enzyme most responsible for the synthesis of melanin. Albinism is an inborn error due to lack of synthesis of melanin. It is an autosomal recessive disorder with a frequency of 1 in 20,000.

Ref: Textbook of Biochemistry and Human Biology by G. P. Talwar, 3rd Ed, Page 452

Ans. Pink

Ans. Glaucoma

Ans. B: Normal production of melanin

Oculocutaneous albinism is inherited as an autosomal recessive trait.

Ocular albinism results from mutation in a gene on the X chromosome, which maps to band Xp22.3-22.2 and is inherited as an X-linked recessive trait.

Two main variants:

Tyrosinase positive are usually less severe whereas tyrosinase negative are more severe

Molecular defect is absent/sparse production of melanin.

Pateint presents with total absence of melanin in skin, hair and eyes.

They are prone to develop squamous cell carcinoma of skin induced by ultraviolet rays, which develops on photo-exposed parts due to lack of protective melanin.

Ans. b. Eye consultation

Ans. is ‘a’ i.e., Tyrosinase

Ans. is ‘a’ i.e., Red reflex 

• All the given options are seen in albinism. But, red reflex is specific.
• Ocular features in albinism –
• a Red reflex
• Pink or blue iris
• Dazzling glare
• Photophobia
• Decreased vision
• Nystagmus
• Clear retinal and choroidal vessels, separated by glistening white space
•  Strabismus (mild to moderate)