I was born with moderate PKU. My levels were pretty low and after 3 years old I was off diet for 35 years. Now I have possible brain damage because over the years my levels rose to 1800 moles/liter. Which is 60 mg/dl on the old scale. It was never that high when I was a teen. Watch the levels for life. Doctor are not sure. My doctor has never seen anyone like me or even heard of anyone like me. I have constant dizziness and problems concentrating including driving a car. NEVER let your guard down.