PGD analysis for aneuploidy in a patient heterozygous for a polymorphism of chromosome 16 (16qh-)

Objectives Detection and study of a polymorphism of chromosome 16qh in preimplantational embryos as well as in peripheral blood from the carrier. Methods A polymorphism of chromosome 16 (16qh-) was detected in PGD analysis for aneuploidy using a probe for the centromeric region of chromosome 16. The lack of pericentromeric heterochromatin in one of the chromosomes 16 could lead to misdiagnosis in PGD. PGD analysis using telomeric probes for this chromosome was performed to confirm the polymorphism as well as to avoid misdiagnosis in embryo blastomeres. FISH in lymphocyte metaphases was used to detect the carrier. Results Telomeric probes allowed detection of a polymorphism for the centromeric region of chromosome 16. FISH with centromeric and telomeric probes in lymphocyte metaphases of the parents showed that the patient was the carrier of the polymorphism. Conclusion It is highly recommended that telomeric probes for chromosome 16 be used in preimplantation genetic diagnosis when a high frequency of monosomy for chromosome 16 is observed after regular aneuploidy analysis. Copyright (C) 2004 John Wiley Sons, Ltd.