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Fig. 1 | Orphanet Journal of Rare Diseases

Fig. 1

From: Diagnostic and therapeutic recommendations for the treatment of hyperphenylalaninemia in patients 0–4 years of age

Fig. 1

Diagnosis algorithm of different types of PKU. BH4: Tetrahydrobiopterin; DHPR: Dihydropteridine reductase; GTPCH: Guanosine triphosphate cyclohydrolase; PAH: Phenylalanine hydroxylase; Phe: Phenylalanine; PKU: Phenylketonuria; PTPS: 6-pyruvoyl-tetrahydropterin synthase. We recommend that a full panel of investigations is conducted, even in patients with unknown genotype who do not respond in the BH4 loading test. This will ensure that the subtype of PKU can be identified, which may be beneficial for the ongoing management of the patient

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