title: Letter: Mongolism by tertiary trisomy.
mesh_terms: D000328:Adult; D002869:Chromosome Aberrations; D002903:Chromosomes, Human, 19-20; D002904:Chromosomes, Human, 21-22 and Y; D004314:Down Syndrome / Q000175:diagnosis / Q000209:etiology / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D012730:Sex Chromosomes; D013194:Staining and Labeling; D014314:Trisomy