What is the theme in Kira-Kira by Cynthia Kadohata?

Coming of age is the main theme. In the novel, Kira-Kira, we watch Katie grow from a tiny nearly five year old into a heartbroken, mature eleven years old. In the beginning, the world seems new and fresh to her, a place where nothing could possibly go wrong as long as her sister, her favorite stuffed animal, and her parents are within easy reach. She trusts that if anything bad should happen, Lynn would be there to rescue her as she did when the dog attacked. As she grows older, forced into a sort of accelerated maturity by Lynn's recurring illness, Katie quickly learns to rely on herself. It is also in caring for her baby brother she shares the lessons Lynn taught her and becomes a more responsible child.