Translocation (13q21q).  Four generation family study with analysis of satellite associations, fluorescent markers, and prenatal diagnosis.
A (13q21q) translocation was found in an infant with Down's syndrome.  The 17-year-old mother and the grandmother carried the translocation 45,XX,t(13;21)(p12;q11).  The great grandparents had normal karyotypes.  Fluorescence marker studies suggested that the translocation originated in the great grandmother.  The hypothesis was supported by satellite association studies which showed a significant excess of 13-21 and 13-15 associations in the great grandmother.
D000649:Amniocentesis; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000032:analysis; D002901:Chromosomes, Human, 13-15; D002904:Chromosomes, Human, 21-22 and Y; D004314:Down Syndrome / Q000175:diagnosis / Q000235:genetics; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008856:Microscopy, Fluorescence; D010375:Pedigree; D014178:Translocation, Genetic