dmcn12197-sup-0001-VideoS1.movvideo/mov4179KVideo S1. Continuous, 1Hz, rhythmic, figure-of-eight head stereotypy and dyskinetic hand movements that briefly settled during a period of concentration (patient 1 at 13 years).
dmcn12197-sup-0002-VideoS2.movvideo/mov2933KVideo S2. Truncal stereotypies rocking constantly from side-to-side in concert with the slow figure-of-eight head and hand stereotypies when lying on the floor (patient 1 at 14 years).
dmcn12197-sup-0003-VideoS3.movvideo/mov8897KVideo S3. Figure-of-eight head stereotypy and dyskinetic hand movements that increased with excitement but settled with concentration and was associated with smiling and sometimes vocalization (patient 2 at 9 years).
dmcn12197-sup-0004-VideoS4.movvideo/mov4415KVideo S4. A fast (2–3Hz) head stereotypy of a side-to-side ‘no’ movement occurring in isolation or in conjunction with complex right upper limb stereotypy where she flicked her ear with her right hand (patient 3 at 11 years).

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