User talk:130424929

 ROBERTSONIAN TRANSLOCATIONS

Robertsonian translocations is a special type of nonreciprocal translocation,in which two nonhomologous acrocentric chromosomes undergo fusion of their short arms yealding a chromosome which a single functional centeromere.

these translocations are important in human genetics specially as a risk factor to be concidered in down syndrome.When chromosome 21 is one of the acrocentrics in a robertsonian translocation,the rearrangement leads to a familial type of down syndrome in which the risk of recurrance is very high.Approximately 3 percent of children with down syndrome are found to have one parent with such translocation. (Hartl,L.Daniel and  Ruvolo,Maryellen Analysis of genes and genomes 8th edition Canada:World headquaters pg286-287)

normal chromosome --->centeromeric fusion----> Robertsonian translocations.