First of all congratulations on your new son! I know you and your wife are probably feeling overwhelmed and afraid, but your son will be okay. With proper treatment he will lead a happy, healthy, and completely normal life.
I am not sure how well PKU has been explained to you and your wife, so if I say something that you do not understand PLEASE feel free to ask questions. PKU is caused when someone has a missing enzyme or an enzyme that does not work properly. This specific enzyme is used to break down an amino acid (or a small piece of protein) called phenylalanine. In people who do no have PKU the working enzyme changes phenylalanine into a new enzyme called tyrosine. Because your son and others who have PKU (myself included) do not have a working enzyme they cannot change phenylalanine into tyrosine, and phenylalanine can accumilate in the blood stream. This is why people who have PKU have phenylalanine levels higher than people who do not have PKU.
People who do not have PKU typically have a phenylalanine level between 0.5 and 1 milligrams of phenylalanine/decaliter of blood (mg/dl). People born with PKU have much higher phenylalanine levels, so they must be placed on a special low protein diet to bring these levels down. Doctors recommend that people who have PKU keep their phenylalanine levels between 2 and 6 mg/dl. This means that your sons levels are a little bit higher than recommended, but with the special formula that the doctors gave you his levels should come down.
As far as whether or not he is being given too much formula the amount of formula each person with PKU has to take varies. Because he is drinking the Penflex-1 before breast feeding he will probably breast feed less, so in the end he will probably end up drinking the same amount of liquids. The only difference is that instead of drinking straight breast milk part of his feeding will be with the formula. The formula is very important, because it provides your son with all of the nutrients he needs except the formula does NOT contain phenylalanine. If your son only received breast milk he would get the necessary nutrients, but he would get too much phenylalanine…does that make sense?
I hope this helped to clear up a few of your questions. If you have any more questions please feel free to ask them, and I (along with others on this website) will be more than happy to help you in anyway possible.
~Breanna Hardy 18 with classical PKU