Figure 2From: Tetrahydrobiopterin responsiveness in phenylketonuria: prediction with the 48-hour loading test and genotypeTreatment results in patients with true-positive BH4 responsiveness. (A) Histogram of the increase in natural protein intake (g/day). (B) Histogram of the percentage change in phenylalanine concentration. (C) Combined overview of the increase in natural protein intake (g/day) and the absolute change in phenylalanine concentration.Back to article page