title: Maternally transmitted extra ring (21) chromosome in a boy with Down's syndrome.
mesh_terms: D002869:Chromosome Aberrations; D002904:Chromosomes, Human, 21-22 and Y; D004314:Down Syndrome / Q000235:genetics*; D004912:Erythrocytes / Q000201:enzymology; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008297:Male; D013482:Superoxide Dismutase / Q000097:blood
chemical_list: D013482:Superoxide Dismutase