Deficiencies in the enzymes required to synthesize or recycle BH4 result in a clinical syndrome that is largely indistinguishable from PKU, as BH4 is a necessary cofactor in the reactions catalyzed by PAH.
These disorders are inherited in an autosomal recessive fashion and treatment ES with oral replacement of BH4.
Metabolism of tetrahydrobiopterin (BH4) is deficient in a small subset of patients with phenylketonuria (PKU). The majority of patients with PKU have a deficiency in the enzyme phenylalanine hydroxylase (PAH) that converts phenylalanine to tyrosine. Deficiency results in accumulation of phenylalanine and its metabolites phenylacetate and phenyllactate.
However defects in enzymes
that either produce or recycle BH4 can have similar clinical manifestations since BH 4 is a required cofactor for the function of PAH. It is also used as a cofactor for the enzymes tyrosine
hydroxylase and tryptophan hydroxylase.
Autosomal recessive mutations in
these enzymes result in impaired metabolism and recycling of BH4.
Clinical manifestations include neurotransmitter deficiency in addition to symptoms normally associated with PKU: microcephaly, skin disease, seizures, and intellectual disability.
submitted by โnamesthegame22(13)
Deficiencies in the enzymes required to synthesize or recycle BH4 result in a clinical syndrome that is largely indistinguishable from PKU, as BH4 is a necessary cofactor in the reactions catalyzed by PAH.
These disorders are inherited in an autosomal recessive fashion and treatment ES with oral replacement of BH4.
Metabolism of tetrahydrobiopterin (BH4) is deficient in a small subset of patients with phenylketonuria (PKU). The majority of patients with PKU have a deficiency in the enzyme phenylalanine hydroxylase (PAH) that converts phenylalanine to tyrosine. Deficiency results in accumulation of phenylalanine and its metabolites phenylacetate and phenyllactate.
However defects in enzymes that either produce or recycle BH4 can have similar clinical manifestations since BH 4 is a required cofactor for the function of PAH. It is also used as a cofactor for the enzymes tyrosine hydroxylase and tryptophan hydroxylase.
Autosomal recessive mutations in these enzymes result in impaired metabolism and recycling of BH4.
Clinical manifestations include neurotransmitter deficiency in addition to symptoms normally associated with PKU: microcephaly, skin disease, seizures, and intellectual disability.