Question

Analyze the pedigree chart that is given below and select the correct option.

• 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 a recessive sex - linked disease like haemophilia

Answer 1

Answer: (B)

The given pedigree shows the inheritance of a condition such as phenylketonuria as an autosomal recessive trait. Since the parents are normal and children are affected, the disease is in recessive form. In first-generation, both males and females are equally affected. Since the disease is recessive, for a girl to be affected by an unaffected father, the disease has to be autosomal recessive.