A person who is developmentally disabled, i.e., if he or she or she has a disability attributable to mental retardation, cerebral palsy, epilepsy, autism or another neurological condition found by the United States Secretary of Health and Human Services to be closely related to mental retardation or to require treatment similar to that required for mentally retarded individuals, which disability originates before such individual attains age 18, and which constitutes a substantial handicap to such individual.