Ruth- With proper treatment your niece will be fine. Alyna will need to follow a special low protein diet, drink the formula that the hospital gave your sister, and she will need to do regular blood tests. Your sister can definitely continue breastfeeding her daughter. Seventeen years ago when I was born my mother was told she could not breastfeed me, but today many children with PKU are breastfed and doing great today! I have two younger sisters who are ten years old and eight months and they both have PKU. My mother breastfed both of them and they are doing great today. My eight month sister is actually beginning to talk!! As for how long your niece will have PKU, it is a life long disorder. She will need to remain on the diet for life. My personal experience with PKU has never been hard. My parents have always remained positive about my PKU and trust me their positive attitudes have rubbed off on me! My thinking is that life could be worse. Despite the fact that I have PKU I am happy, healthy, and fully functional. In August I will be attending college. I will be studying Nursing and Pre-med. When someone is born with other disorders such as down syndromes, they are not given the option of following a diet and living a completely normal life. For the most part having PKU is just about making diet modifications. If you, your sister, and your family treat PKU as a part of life as Alyna grows up that will most likely be how she thinks of it. I know right now PKU does not seem like ‘just a part of life,’ but as time goes on dealing with PKU will become second nature.