Therapists have used paper-based exercises to treat learning disorders for many years. Dyslexia and Dysgraphia are one of the reading and writing disorders that are common nowadays. Different serious games and interventions are developed for the improvement of dyslexic and dysgraphic children. But these games cannot engage these children for a long time. Moreover, there is a need for an assessment criterion for the performance of dyslexic and dysgraphic children. Augmented Reality is an emerging technology that is used in the educational and medical fields. Augmented Reality in learning apps increases children's performance and makes them attentive. Research shows that it has a positive impact on dyslexic children. In this case study, an augmented reality-based serious game called ARLexic Game is developed to train children with Dyslexia and Dysgraphia. Design Science Research Methodology is used to design and develop the application. An experiment is conducted with specialists in special education and children with dyslexia and Dysgraphia aged 7 to 14 years old. The outcome shows that the ARLexic Game engagement level increases with time. Children learn quickly without being bored and enjoying it.