Phenylketonuria (a metabolic disorder of phenylalanine, resulting in dementia) is inherited as an autosomal recessive trait.

Phenylketonuria (a metabolic disorder of phenylalanine, resulting in dementia) is inherited as an autosomal recessive trait. What kind of children can be in a family where parents are heterozygous for this trait?

Phenylketonuria is inherited as an autosomal recessive trait, that is, the disease manifests itself only in a homozygous state.
Let A – normal metabolism, and – phenylketonuria. If the parents are heterozygous, then they are both healthy and their genotype is Aa.
RR g Aa (h) x m Aa (h)
m / f
AND
and
AND
AA (h)
Aa (h)
and
Aa (h)
aa (f)
The probability of having children with phenylketonuria in this family is 25%. Since this is an autosomal gene, that is, not linked to sex chromosomes, it can be both boys and girls.