How common is savant syndrome?
Approximately one in ten (10%) of persons with autistic disorder have some savant skills. In other forms of development disability, mental retardation or brain injury, savant skills occur in less than 1% of such persons (approximately 1:2000 in persons with mental retardation). Since these other forms of mental disability are much more common than autistic disorder however, it turns out that approximately 50% of persons with savant syndrome have autistic disorder, and the other 50% have some other form of developmental disability, mental retardation or brain injury or disease. Thus not all savants are autistic, and not all autistic persons are savants.