The correct answer is chromosome translocation.
Chromosome translocation refers to a chromosome unusualities resulting due to the reorganization of the components between the non-homologous chromosomes. A fusion of gene may be produced when the translocation connects two otherwise-different genes. It is determined on karyotype of affected cells or on cytogenetics.
Down syndrome is a disorder caused in a few of the cases by a Robertsonian translocation of the chromosome 21 long arm onto the long arm of chromosome 14.