14 14 Reunite of the 14 two long arms 21q 14q 14q Breakage at centromere 21p Reunite of the 21p two short arms 21 q入 4p 21 Pathogenesis of translocation in 21-trisomy14q 14p 21q 21p Pathogenesis of translocation in 21-trisomy 21q 21p 14q 14p Breakage at centromere 14q 21q Reunite of the two long arms 14p Reunite of the 21p two short arms