We have been researching and developing the Augmentative and Alternative Gesture Interface (AAGI) for over 10 years to support people with motor disabilities. The gesture interface consists of nine different recognition modules, which are first selected according to the user's desired movement. Then the system learns the gestures of different individuals with disabilities and uses their movements as the interface for actions such as controlling a computer. This paper presents a case study in which this gesture interface was implemented for a child with cerebral palsy who is unable to use various switches and other devices. He was able to raise his hand unconsciously. We utilized the AAGI's front module to teach him interaction. He could not raise or lower his hands on his own voluntarily, so his mother held his hands and made them go up and down to teach his gesture to the system. Then we set a toy to move when he lifted his hand. His mother repeatedly moved his hand and taught him that when he raised his hand, the toy would move. This trial was conducted once a week for six consecutive weeks. Then, on the fourth week, he began to raise his hand spontaneously. After practicing this movement for six consecutive weeks, he was able to understand that he could move the toy by lifting his hand.