Dynamic nuclear polarization at very low magnetic fields

Non-mosaic Klinefelter patients are generally azoospermic due to primary testicular failure. Nevertheless, in some cases, testicular spermatozoa may be recovered and utilized to fertilize oocytes via intracytoplasmic sperm injection (ICSI). As the risk for an increased number of gonosomes in these spermatozoa is unclear, preimplantation genetic diagnosis (PGD) may be attempted in the resulting embryos. In the present study, we report our experience with the combined approach of sperm retrieval by testicular fine needle aspiration (FNA), ICSI and PGD in seven consecutive non-mosaic Klinefelter individuals. In four patients, between one and five spermatozoa were retrieved in five out of nine consecutive attempts. In a fifth patient, only 10 round spermatids could be isolated. Mature spermatozoa were injected into a total of 16 metaphase-II oocytes, of which 11 (69%) remained intact. Two distinct pronuclei (2PN) were observed in four oocytes (36%) while a single pronucleus (1PN) was documented in two oocytes. Five cleavage stage embryos developed from the oocytes of two couples. Upon the request of one couple, their three embryos (two derived from 1PN oocytes) were transferred without PGD but pregnancy was not achieved. PGD by fluorescence in-situ hybridization (FISH) was performed in the two embryos of the other couple which were derived from normal fertilization. PGD results of one embryo were 18,18,X,X,Y, the embryo was not transferred and FISH analysis of the remaining blastomeres identified variable chromosome numbers in the nuclei. The second embryo was diagnosed as normal and was transferred, resulting in a successful pregnancy and birth. In conclusion, the results of this report indicate that a pregnancy and birth may be attained in azoospermic non-mosaic Klinefelter individuals by testicular FNA combined with ICSI. Due to the unknown risk of gonosomes aneuploidy in embryos from Klinefelter patients, PGD or prenatal diagnosis should be recommended.