Severe mental retardation in children in a northern Swedish county.
D000293:Adolescent; D001724:Birth Weight; D002648:Child; D002675:Child, Preschool; D005260:Female; D005865:Gestational Age; D006801:Humans; D008607:Intellectual Disability / Q000150:complications / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D012737:Sex Factors; D013548:Sweden