i would call them right away, it may be nerological or becuase she is delayed. though when i was a kid i tripped alot, over anythign and im still very clumbsy, and its not pku related its my bones adn my body. as a kid ihad to have specal shoes made of had to wear hiking boots cause i have week ankles and fell over alot cause they clould hold my legs and me up, this may be something to have looked at to. it could be that her bones are to week adn she may have a iron or calcium definceny. nim sorry i cant be more help , i havent really heard alot on the subjcet. let me know what u find out, id be curious to know.