Reciprocal translocation 5;12 carier in a case with trisomy 21

İt was suggested that translocations and other chromosomal rearrangements disturb meiotic disjunction mechanism and increase predisposition to trisomic offsprı'ngs. VVe report a case with Down syndrome whose karyotype was 47,XY,t(5;12)(5pter->5q11 ::12q24->12qter;12pter->12q24::5q11-> 5qter),+21. Because of the absence of any phenotypic findings, except Down syndrome stigmata, he has been accepted as a balanced translocation carrier with trisomy 21. His father was a carrier of this translocation so, the possible effect of parental translocations to the meiotic disjunction was discussed.