Question

Study the given pedigree chart. Find out the inheritance pattern of disease.

• A. Inheritance of a sex-linked inborn error of metabolism like phenylketonuria.
• B. Inheritance of a condition like phenylketonuria as an autosomal recessive trait.
• C. The pedigree chart is wrong as this is not possible.
• D. Inheritance of an autosomal dominant disease like Huntington disease.

Answer 1

The correct option is B Inheritance of a condition like phenylketonuria as an autosomal recessive trait.

• The pedigree chart shows the inheritance of an autosomal recessive trait, as children of normal parents are affected. This is possible only in the case of a recessive inheritance because both parents are carriers of the disease.
• Apart from that, both male child and female child are affected in second-generation so there are higher chances that pedigree belongs to an autosomal inheritance.
• An example of an autosomal recessive trait is phenylketonuria.

So, the correct answer is 'Inheritance of a condition like phenylketonuria as an autosomal recessive trait.'