"Developmentally disabled" means a person with a disability attributable to mental retardation, cerebral palsy, epilepsy or other neurologically handicapping condition found to be closely related to mental retardation or to require treatment similar to that required for mentally retarded children. Such disability originates before an individual attains age 18, continues, or can be expected to continue, indefinitely and constitutes a substantial handicap for such individual.
Cal. Code Regs. Tit. 22, § 73027