Evaluation of Behavior, Executive Function, Neurotransmitter Function and Genomic Expression Kuvan Nonresponders

"In 30 PKU patients found previously to exhibit no decrease in blood PHE levels behavioral and cognitive function, neurotransmitter levels, and gene expression of enzyme activity will be measured at baseline and after 4 weeks of Kuvan administration. Rating inventories of executive function performance and behavior will be administered to patients and parents.~Urine neurotransmitters, blood microarray expression, and plasma amino acids will be measured (plasma PHE and TYR levels will also be measured at weeks 1 and 2). Nutrient analysis of 3 day food diaries will be conducted."