Double Aneuploidy: Trisomy 18 and XXY in a Boy

The simultaneous occurrence of double aneuploidy in the same individual is a relatively rare phenomenon. Most of the previously reported cases of double trisomy were found in spontaneous abortions. We report on a male newborn presenting with typical clinical features of Edwards syndrome (trisomy 18), resulting from de novo, non-mosaic 18 trisomy with an additional X in the karyotype: 48, XXY, +18. Besides the typical features of trisomy 18 (prominent occiput, clenched hands, rocker-bottom feet, congenital heart disease, diaphragmatic hernia and recurrent respiratory tract infections), the patient has overlapping features with Klinefelter syndrome (cryptorchidism). A molecular cytogenetic method with digoxigenin-labeled probes D18Z1 and DXZ1 was used to confirm the diagnosis, and to clarify the non-mosaic status of Edwards syndrome and the coexistence of Klinefelter syndrome. The XXY constitution may have contributed to the development of normal height and absence of microphthalmia in this patient with trisomy 18. This patient remains alive up to the present time (21 months). To our knowledge, this is the first case of Edwards syndrome together with Klinefelter syndrome in Taiwan. The literature regarding double aneuploidy, which combines both autosome and sex chromosome aberrations, was also reviewed. (Chang Gung Med J 2006;29(4 Suppl):6-12)