title: Down's syndrome: chromosome analysis in 321 cases in Japan.
mesh_terms: D000367:Age Factors; D000782:Aneuploidy; D001345:Autoradiography; D002869:Chromosome Aberrations; D002904:Chromosomes, Human, 21-22 and Y; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D014314:Trisomy