inborn disorder of amino acid metabolism tetrahydrobiopterin (BH4)-deficient hyperphenylalaninemia https://www.malacards.org/card/tetrahydrobiopterin_deficient_hyperphenylalaninemia GARD:0026632 MONDO:0850519 DOID:0081132 An amino acid metabolic disorder that are characterized phenotypically by hyperphenylalaninemia, depletion of the neurotransmitters dopamine and serotonin, and progressive cognitive and motor deficits and that has material basis in autosomal recessive mutations in the genes encoding enzymes involved in the synthesis or regeneration of BH4.