Regarding assertion and reason, select the correct option
Assertion [A]: Phenylketonuria or PKU is a disease that can affect both females and males
Reason [R]: The individual should be homozygous recessive to get PKU
Regarding assertion and reason, select the correct option
Assertion [A]: Phenylketonuria or PKU is a disease that can affect both females and males
Reason [R]: The individual should be homozygous recessive to get PKU
The correct option is D Assertion [A] is True and Reason [R] is True but is an incorrect explanation to [A].
While it is true that an individual has to be homozygous recessive to be affected by PKU, it does not explain why PKU can affect both males and females equally. The correct reason for this is the presence of the gene on an autosome. Therefore it follows autosomal recessive inheritance pattern. PKU is inherited in families in an autosomal recessive pattern. Autosomal recessive inheritance means that a person has two copies of the gene that is altered. Usually, each parent of an individual who has PKU carries one copy of the altered gene. Since each parent also has a normal gene, they do not show signs or symptoms of PKU. Gene alterations (mutations) in the PAH gene cause PKU. Mutations in the PAH gene cause low levels of an enzyme called phenylalanine hydroxylase. These low levels mean that phenylalanine from a person's diet cannot be metabolized (changed), so it builds up to toxic levels in the bloodstream and body. Having too much phenylalanine can cause brain damage unless diet treatment is started.
Assertion [A] is True and Reason [R] is True but is an incorrect explanation to [A].
While it is true that an individual has to be homozygous recessive to be affected by PKU, it does not explain why PKU can affect both males and females equally. The correct reason for this is the presence of the gene on an autosome. Therefore it follows autosomal recessive inheritance pattern. PKU is inherited in families in an autosomal recessive pattern. Autosomal recessive inheritance means that a person has two copies of the gene that is altered. Usually, each parent of an individual who has PKU carries one copy of the altered gene. Since each parent also has a normal gene, they do not show signs or symptoms of PKU. Gene alterations (mutations) in the PAH gene cause PKU. Mutations in the PAH gene cause low levels of an enzyme called phenylalanine hydroxylase. These low levels mean that phenylalanine from a person's diet cannot be metabolized (changed), so it builds up to toxic levels in the bloodstream and body. Having too much phenylalanine can cause brain damage unless diet treatment is started.
