A young boy with a rare genetic disorder found his symptoms eased after drinking coffee, according to scientists. The boy had a genetic disorder known as ADCY5-related dyskinesia. Caused by mutations in the ADCY5 gene, the condition is characterized by involuntary movements, including jerking, twitching, tremors, tensing muscles and writhing that can affect the face, limbs and neck. According to the U.S. National Library of Medicine, at least 400 people have been diagnosed with the disease. However, there are likely more sufferers as the symptoms may be confused for cerebral palsy or epilepsy.