title: [Severe mental retardation in children: incidence, prevalence, etiology and multihandicap].
mesh_terms: D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000453:epidemiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D008297:Male; D012189:Retrospective Studies; D013548:Sweden
vernacular_title: Grav mental retardation hos barn: incidens, prevalens, etiologi och multihandikapp.