Unreported defect in the siblings of retarded children.
D002648:Child; D002653:Child Behavior Disorders / Q000235:genetics; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D007361:Intelligence Tests; D008425:Maternal Behavior; D009034:Mother-Child Relations; D011581:Psychological Tests; D012561:Schizophrenia, Childhood / Q000150:complications / Q000235:genetics; D012959:Socioeconomic Factors