Figure 3From: Tetrahydrobiopterin responsiveness in phenylketonuria: prediction with the 48-hour loading test and genotypeOutcome . The outcome of the 48-hour BH4 loading test and the BH4 extension phase in patients with (A) 2 Putative Null mutations (B) Compound heterozygosity (C) 2 mutations associated with true BH4 responsiveness.Back to article page