California Code, Probate Code - PROB § 1420

“Developmental disability” means a disability that originates before an individual attains 18 years of age, continues, or can be expected to continue, indefinitely, and constitutes a substantial handicap for the individual. As defined by the Director of Developmental Services, in consultation with the Superintendent of Public Instruction, this term includes intellectual disability, cerebral palsy, epilepsy, and autism. This term also includes handicapping conditions found to be closely related to intellectual disability or to require treatment similar to that required for individuals with an intellectual disability, but does not include other handicapping conditions that are solely physical in nature.