Preimplantation genetic diagnosis of a reciprocal translocation t(3;11)(q27.3;q24.3) in siblings

Preimplantation genetic diagnosis (PGD) was performed in two couples to avo id chromosomally unbalanced progeny in a family in which a brother and a si ster carry an identical maternally inherited balanced translocation t(3;11) (q27.3;q24.3). Embryos were biopsied 3 days after fertilization and blastom eres were analysed by fluorescent in-situ hybridization (FISH). Embryos wer e classified as unbalanced or normal/balanced. In the first case, the male carrier and his wife underwent one IVF/PGD treatment cycle. In all, 18 embr yos were analysed. Of those, 15 revealed an unbalanced karyotype, For one e mbryo, results were not conclusive, from one embryo results were contradict ory and one embryo was classified as normal/balanced and subsequently trans ferred. A singleton pregnancy was achieved. The PGD analysis was confirmed at 16 weeks gestation by amniocentesis. At term, a healthy girl with a bala nced karyotype was born. Pregnancy and delivery were without complications. In the second case, the female carrier and her husband underwent two IVF/P GD treatment cycles. During the first cycle, three embryos were analysed. O ne embryo revealed an unbalanced karyotype and two embryos were designated a normal/balanced karyotype and transferred but no pregnancy was achieved. During the second PGD cycle three embryos were analysed. Of those, none app eared suitable for transfer. The couple decided not to undergo further trea tment. Our results indicate that for individuals carrying a reciprocal tran slocation PGD is a feasible approach to obtain embryos with a normal chromo some balance and to avoid both spontaneous and induced abortion.