Question

Identify the correctly matched pair from the following?

• A. Down's syndrome - Mutation in a single gene
• B. Klinefelter syndrome - Absence of one X-chromosome
• C. Sickle-cell anaemia - Presence of an additional X chromosome
• D. Albinism - Mutation in a single gene

Answer 1

The correct option is D Albinism - Mutation in a single gene

• Albinism is a genetic disorder which arises due to the mutation in a single gene which is responsible for producing melanin.
• Due to the absence of this pigment, skin is pale, hair is white, eyes are usually pink because of the absence of the pigment in retina and sclera.
• Down syndrome is caused due to the presence of an additional copy of chromosome 21.
• Klinefelter syndrome is caused due to the presence of an additional copy of X-chromosome in males.
• Sickle-cell anaemia is caused due to a mutation in the gene that codes for haemoglobin. This replaces valine with glutamic acid at the sixth position of the haemoglobin chain.