Question
Biology Question on Principles of Inheritance and Variation
Which one is a hereditary disease?
A
cataract
B
leprosy
C
blindness
D
phenylketonuria.
Answer
phenylketonuria.
Explanation
Solution
Phenylketonuria is a hereditary disease. Phenylketonuria is an inherited error of metabolism caused by a deficiency in the enzyme phenylalanine hydroxylase. It results in mental retardation and is inherited as an autosomal recessive trait. It is a hereditary human condition resulting from the inability to convert phenylaline into tyrosine. This change can be traced to a tiny mutation in a single gene on chromosome 12.