In California, Regional Centers provide services and supports to people with developmental disabilities under a law called the Lanterman Act. To get these services, a person must have a qualifying developmental disability. The law lists five types: (1) intellectual disability; (2) cerebral palsy; (3) epilepsy; (4) autism; and (5) a “Fifth Category”, which covers conditions that are closely related to intellectual disability, or that require treatment similar to what people with intellectual disability need. The Fifth Category matters because some people do not fit neatly into the other four categories but still need the same kind of help as people with intellectual disability. For example, a person may have serious thinking, learning and everyday-life problems even if their IQ score is a little above the usual cutoff. Understanding the basic rules can help people with intellectual and developmental disabilities and their supporters respond when a Regional Center says no.