Characterization of a de novo unbalanced translocation t(14q18q) using microdissection and fluorescence in situ hybridization

We report on a patient with a de novo translocation between the long arms of chromosomes 14 and 18. The translocation was studied using microdissection in combination with fluorescence in situ hybridization (micro‐FISH). Five copies of the chromosomes involved in the translocation were isolated by microdissection and amplified by means of degenerate oligonucleotide primed‐polymerase chain reaction (DOP‐PCR). Reverse chromosome painting with the biotin‐labeled PCR product showed that part of the q‐arm of chromosome 18 had no signal. The deletion was characterized further by FISH with band‐specific probes and it was concluded that the rearrangement was unbalanced: 46,XY,t(14;18)(14pter→4q22::18q21.1→18qter)(18pter→18q12.2::14q22→14qter). The patient, who presented with psychomotor retardation, mild obesity, pes equinovarus, strabismus, and facial anomalies, is compared with previously reported patients with an interstitial deletion of band 18q12. Am. J. Med. Genet. 75:409‐413, 1998. © 1998 Wiley‐Liss, Inc.