Humangenetik und Embryologie

The recent discovery of PRRT2 mutations in Paroxysmal Kinesigenic Dyskinesia (PKD) has spurred a number of studies on PRRT2 mutations and PRRT2 disorders including PKD, Benign Familial Infantile Epilepsy (BFIE), and Infantile Convulsions with Choreoathetosis (ICCA). Mutated PRRT2 is also implicated in several other paroxysmal neurological disorders, indicating a wide phenotypic spectrum of PRRT2 mutations. Although the correlations between PRRT2 mutations and specific phenotype have not been well investigated, our previous studies have shown that PRRT2 mutations carriers may have a distinct clinical feature and drug response with non-PRRT2 mutations carriers. Yeast two-hybrid studies have suggested that PRRT2 interacts with synaptosomal associated protein 25 (SNAP25), which is involved in synaptic vesicle handling and neuronal exocytosis. Therefore, the pathogenesis of PRRT2 disorders is probably associated with synaptic dysfunction. Further studies are needed to elucidate the role of PRRT2 and the potential mechanism of PRRT2 disorders.

During the last years, vitrification was introduced into clinical practice. Although vitrification counts several years of experimental studies, this method is still under development. In this study, a new vitrification protocol was evaluated. Materials and methods: An experimental study conducted in a University laboratory evaluated a new, short vitrification protocol including two vitrification and two thawing solutions, made in-house. The vitrification solutions contained dimethyl sulfoxide, ethylenoglycol and human serum albumin. The thawing solutions contained sucrose and human serum albumin. Rat oocytes, allocated in two groups, were used. In the control group, the oocytes were vitrified using a standard protocol. In the experimental group, the oocytes were vitrified using the new protocol. The endpoint was the survival rate of the oocytes just after thawing and 48 hours later. Results: The survival rate just after thawing was similar in the two groups (62.5% for the control group and 60% for the experimental group, p=0.18). However after 48 hour incubation, there was a significant difference between the two groups: 55% survival for the control group and 45% for the experimental group (p=0.008). Conclusion: The two vitrification protocols achieved similar survival rates just after thawing. However, after 48 hours incubation of thawed oocytes, the standard method had higher survival rates, than the in-house one.

Vitrification devices are of considerable importance for the successful vitrification of gametes and embryos. They have to be easy to use and achieve good results. We compared the plastic blade, a new in-house device, to McGill Cryoleaf regarding the convenience of the use and the survival rate of vitrified human abnormal oocytes and embryos after thawing. Material and methods: Abnormal oocytes and embryos derived from women who underwent I.V.F treatment, were used in this study. Two groups were included. In the control group, abnormal oocytes and embryos were vitrified with the Cryoleaf; in the second group, it was used the plastic blade. In both groups, vitrification followed a standard and commercially available protocol. Results: A number of problems appeared in the use of plastic blade during handling under liquid nitrogen and during placing the device into the warming solution. The survival rates of the vitrified oocytes (61.53%) and embryos (42.86%) with the plastic blade were significantly lower than with McGill Cryoleaf (80% and 61.54% respectively). Conclusion: Plastic blade is not as effective as McGill Cryoleaf. Further improvements could establish it as an alternative vitrification device.