title: Origin of the extra chromosome no. 21 in Down's syndrome.
abstract: Eighteen of 38 examined families with children with Down's syndrome showed polymorphisms of chromosome 21 elucidating the origin of the extra chromosome 21. Maternal origin was found in 10 cases and paternal origin in 8 cases. In both sexes errors occurred both in the first and in the second meiotic division.
mesh_terms: D000328:Adult; D000367:Age Factors; D002904:Chromosomes, Human, 21-22 and Y; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008540:Meiosis; D008875:Middle Aged; D010290:Parents; D010375:Pedigree; D011110:Polymorphism, Genetic; D012737:Sex Factors