Genes and people.
D002869:Chromosome Aberrations; D025063:Chromosome Disorders; D004200:Diseases in Twins; D004314:Down Syndrome / Q000235:genetics; D005826:Genetics, Medical; D006801:Humans; D007361:Intelligence Tests; D010661:Phenylketonurias / Q000235:genetics; D012559:Schizophrenia / Q000235:genetics