Interphase FISH with chromosome-specific protelomere probes for rapid prenatal diagnosis in a reciprocal...

Interphase fluorescence in situ hybridization (FISH) analysis has become an accepted practice for rapid preliminary analysis of chromosome aneuploidy from direct amniocyte preparations. The use of dual-color interphase FISH analysis with chromosome-specific protelomere probes for the rapid exclusion of chromosomally unbalanced segregants in the pregnancy of a reciprocal translocation carrier is reported. Amniocentesis was performed at 16 weeks gestation on the carrier of a t(5;14)(p14.2;p13), who was ascertained after the birth of a son with the der(5) chromosome. Interphase FISH analysis with probes for 5pter, 5qter and 14qter showed two signals for each, consistent with alternate segregation of the maternal translocation. Subsequent metaphase analysis confirmed a 46,XY,t(5;14)(p14.2;p13)mat karyotype in the fetus. This case illustrates the utility of interphase FISH analysis with protelomere probes for rapid prenatal diagnosis in cases of parental reciprocal translocation.