Question

Phenylketonuria is

• A. Sex linked dominant trait
• B. Sex linked recessive trait
• C. Autosomal dominant trait
• D. Autosomal recessive trait

Answer 1

Answer: (D)

Autosomal recessive trait

Autosomal recessive is one of several ways that a trait, disorder, or disease can be passed down through families. An autosomal recessive disorder means two copies of an abnormal gene must be present in order for the disease or trait to develop. Both parents must pass on a nonworking copy of the gene in order for a baby to have the condition. Babies with Phenylketonuria(PKU) are missing an enzyme called phenylalanine hydroxylase. It is needed to break down the essential amino acid phenylalanine. Without the enzyme, levels of phenylalanine build up in the body.

So, the correct answer is 'Autosomal recessive trait'.