Additional chromosome in a child as a result of a balanced reciprocal translocation t(12;18)(p13;q12) in his mother's karyotype.

In this case report we present a child with an additional chromosome in the karyotype. The karyotypes of the boy and his parents were analyzed by use of a conventional banding technique (GTG) and fluorescence in situ hybridization (FISH). Probes painting whole chromosomes 12 and 18 were used in FISH.