<unk>  <unk> D) is a genetic disorder affecting the tetrahydrobiopterin (BH4) synthesis pathway, inherited in the autosomal recessive pattern. It is one of the six known disorders causing tetrahydrobiopterin deficiency, and occurs in patients with mutations of the QDPR gene. The disease presents with such symptoms as elevated levels of phenylalanine (hyperphenylalaninemia), microcephaly, hypotonus, mental retardation and epileptic seizures.
Dihydropteridine reductase deficiency
6-Pyruvoyltetrahydropterin synthase deficiency
Dihydropyrimidine dehydrogenase deficiency
Purine nucleoside phosphorylase deficiency
Glutathione synthetase deficiency
Triosephosphate isomerase deficiency
Adenine phosphoribosyltransferase deficiency
Dihydrofolate reductase deficiency