A person needs 1 pah mutation from each parent to have pku/hpa. Do they need to be the same mutation or can one be ie a300s and one be e390g?

Genetic counselor . At this time, i would not commit my opinion to this very good question. I would seek advice from perinatologist and/or genetic counselor.
PKU inheritance . Very interesting question by the way. It's not necessary to have same gene mutation to have pku. There are around 500 mutations that can result in varying severity of presentation.