The state of Washington defines developmental disability in RCW 71A.10.020(5).

(1) To qualify for DDA you must have a diagnosed condition of intellectual disability, cerebral palsy, epilepsy, autism, or another neurological or other condition found by DDA to be closely related to intellectual disability or requiring treatment similar to that required for individuals with intellectual disability which:

(a) Originates prior to age eighteen;

(b) Is expected to continue indefinitely; and

(c) Results in substantial limitations.

(2) In addition to the requirements listed in subsection (1) of this section, you must meet the other requirements contained in this chapter.