Familial enlargement of the short arm of a small acrocentric chromosome.
D002869:Chromosome Aberrations; D002903:Chromosomes, Human, 19-20; D002904:Chromosomes, Human, 21-22 and Y; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D010375:Pedigree; D014314:Trisomy