title: Twins with mental retardation and physical abnormalities: preliminary report.
mesh_terms: D000328:Adult; D000013:Congenital Abnormalities / Q000235:genetics*; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D008875:Middle Aged