title: Trisomy 21 in a child due to paternal nondisjunction as determined by RFA technique.
mesh_terms: D002675:Child, Preschool; D002904:Chromosomes, Human, 21-22 and Y; D004314:Down Syndrome / Q000235:genetics*; D006801:Humans; D007621:Karyotyping; D008297:Male; D008540:Meiosis; D013194:Staining and Labeling; D014314:Trisomy