I agree with Brea.. a lot of the numbers are showing for off diet PKU people. As a mother to a PKU baby I completely understand where you are coming from. My son is going to be a year old and has ALWAYS been ahead of his milestones… he even started walking at 9 months old. He is very bright and very observant. I think its just important to remember to keep them on diet and watch their levels. I notice when Ian's get higher he does get grumpy… so I keep him on lower phe foods til his levels come back down.