Secondary causes for a stereotypy include:
(1) Rett syndrome
(2) Williams syndrome
(3) Down syndrome
(4) fragile X syndrome
(5) other genetic neurodevelopmental disorders
(6) phenylketonuria
(7) adenylosuccinate lyase deficiency
(8) frontotemporal lobe degeneration
(9) pantothenate kinase-associated neurodegeneration
(10) stroke
(11) significant sensory impairment (visual and/or auditory)
(12) post-streptococcal pharyngitis
(13) encephalitis lethargica
(14) paraneoplastic anti-N-methyl-D-aspartate receptor encephalitis
(15) acquired brain injury (trauma, infection,
(16) autisim spectrum disorder
(17) severe psychiatric disorder
(18) seizure disorder
