Background: Couples who have had multiple miscarriages are at risk for carrying a balanced translocation since these carriers may produce unbalanced gametes. Small imbalances may lead to offspring with multiple congenital anomalies. This report emphasizes the importance of obtaining cytogenetics studies in couples with recurrent spontaneous abortions.
Case: A couple was referred for cytogenetic prenatal testing because of a history of recurrent miscarriages and an infant who died at 6 weeks of age with multiple congenital anomalies. Although the parental chromosomes were previously reported to be normal in another laboratory, the pedigree was consistent with a chromosomal etiology, and parental blood samples were reevaluated. The father was found to carry a subtle reciprocal translocation t(7;11)(q35;q23.3). Slides were obtained from the previous miscarriages and the infant who died. On reexamination, one miscarriage and the infant were found to be chromosomally unbalanced, carrying the derivative 7, resulting in partial monosomy for 7q and partial trisomy for 11q. The other miscarriage had a chromosomally normal female karyotype. Maternal cell contamination could not be excluded in that case. The current pregnancy was found to carry the balanced translocation. Since the rearrangement was quite small and subtle, fluorescence in situ hybridization (FISH) using "painting" probes for chromosomes 7 and 11 was used to confirm the balanced state in the fetus.
Conclusion: This family illustrates the importance of performing high-quality chromosome studies on people who have spontaneous abortions and children with multiple congenital anomalies. The use of FISH probes was helpful in confirming this subtle rearrangement.