Kerrie, I don’t think I’ve ever heard of going to see an endocrinologist for PKU. Maybe if you call one of the metabolic clinics they can let you know if you would need to come there or if you need to see somebody else. Like Amanda said, Classical PKU is the more severe type of PKU. Basically those with CPKU can’t handle as much phe as those with Hyperphe. I’m pretty sure wither you have classical PKU or Hyperphe is based on what your levels are when you first get the new born screening (ie, if you had super high levels when you had the newborn screening done you probably have CPKU). And yes, the formulas have changed soooo much in just my life time.