Creation of a registry for human embryonic stem cells carrying an inherited defect: joint collaboration between ESHRE and hESCreg.

Human embryonic stem cells (hESCs), derived from human blastocysts, hold a great promise for regenerative medicine, drug development and basic research in developmental biology. Moreover, hESC lines that carry a clinically relevant inherited defect, monogenic or chromosomal, present an important tool for research into the pathophysiology of these diseases. The hESC registry (hESCreg) was started up in 2007 in order to register all stem cell lines derived in Europe (www.hescreg.eu). Because of the special nature of the hESC lines that carry an inherited disease, they are of particular interest to researchers outside the assisted reproductive technologies or stem cell fields, for instance, those involved in regenerative medicine and in medical and human genetics. To reach these researchers, and to better disseminate the information on the cell lines, a concerted action of the hESCreg together with ESHRE's Special Interest Groups in Reproductive Genetics and Stem Cells was initiated. This mini-review is a first report that will be followed by yearly reports of new lines, not unlike the reports from the Preimplantation Genetic Diagnosis Consortium or the European IVF Monitoring.

The causes of misdiagnosis and adverse outcomes in PGD.

The European Society of Human Reproduction and Embryology PGD Consortium has collected data on PGD cycles and deliveries since 1997. From 15,158 cycles, 24 misdiagnoses and adverse outcomes have been reported; 12/2538 cycles after polymerase chain reaction and 12/12,620 cycles after fluorescence in situ hybridization. The causes of misdiagnosis include confusion of embryo and cell number, transfer of the wrong embryo, maternal or paternal contamination, allele dropout, use of incorrect and inappropriate probes or primers, probe or primer failure and chromosomal mosaicism. Unprotected sex has been mentioned as a cause of adverse outcome not related to technical and human errors. The majority of these causes can be prevented by using robust diagnostic methods within laboratories working to appropriate quality standards. However, diagnosis from a single cell remains a technically challenging procedure, and the risk of misdiagnosis cannot be eliminated.

CTG repeat instability in a human embryonic stem cell line carrying the myotonic dystrophy type 1 mutation.

Human embryonic stem cells (hESC) are considered to be an indefinite source of self-renewing cells that can differentiate into all types of cells of the human body and could be used in regenerative medicine, drug discovery and as a model for studying early developmental biology. hESC carrying disease-causing mutations hold promise as a tool to investigate mechanisms involved in the pathogenesis of the disease. In this report, we describe the behaviour of an expanded CTG repeat in the 3' untranslated region of the DMPK gene in VUB03_DM1, a hESC line carrying the myotonic dystrophy type 1 (DM1) mutation compared with the normal CTG repeat in two hESC lines VUB01 and VUB04_CF. Expanded CTG repeats were detected by small amount PCR, small pool PCR and Southern blot analysis in consecutive passages of VUB03_DM1. An important instability of the CTG repeat was detected during prolonged in vitro culture, showing stepwise increases of the repeat number in consecutive passages as well as a higher range of variability. This variability was present in cells of different colonies of the same passage and even within single colonies. The high repeat instability is in contrast to the previously observed stability of the repeat in preimplantation embryos and in fetuses during the first trimester of pregnancy. This in vitro culture of affected hESC represents a valuable model for studying the biology of repeat instability.

ESHRE PGD consortium data collection VII: cycles from January to December 2004 with pregnancy follow-up to October 2005.

The seventh report of the ESHRE PGD Consortium is presented documenting cycles collected for the calendar year 2004 and follow-up of the pregnancies and babies born subsequent to these cycles up to October 2005. Since the beginning of the data collections, there has been a steady increase in the number of cycles, pregnancies and babies reported. For data collection VII, 45 centres have participated, reporting on 3358 cycles to oocyte retrieval (OR), 679 pregnancies and 528 babies born. Five hundred and fifty nine OR were reported for chromosomal abnormalities, 113 OR for sexing for X-linked diseases, 520 OR for monogenic diseases, 2087 OR for PGS, and 79 OR for social sexing. Data VII is compared with the cumulative data for data collections I-VI.

ESHRE PGD Consortium data collection VI: cycles from January to December 2003 with pregnancy follow-up to October 2004.

The sixth report of the ESHRE PGD Consortium is presented, relating to cycles collected for the calendar year 2003 and follow-up of the pregnancies and babies born up to October 2004. Since the beginning of the data collections, there has been a steady rise in the number of cycles, pregnancies and babies reported. For this report, 50 centres participated, reporting on 2984 cycles, 501 pregnancies and 373 babies born. Five hundred and twenty-nine cycles were reported for chromosomal abnormalities, 516 cycles were reported for monogenic diseases, 137 cycles were reported for sexing for X-linked diseases, 1722 cycles were reported for preimplantation genetic screening (PGS) and 80 cycles were reported for social sexing. Data VI is compared to the cumulative data for data collections I-V.

Preimplantation genetic diagnosis.

Preimplantation genetic diagnosis (PGD) is an early form of prenatal diagnosis whereby embryos obtained in vitro are tested for the presence of a certain genetic disease. Patients who are at risk to have a child with a genetic disease can thus avoid a prenatal diagnosis and a possible termination of pregnancy. At the Centres for Medical Genetics and Reproductive Medicine, we have applied PGD for monogenic diseases since 1993 and are now one of the largest in the world. In this paper, the theoretical and technical side of PGD will first be explained. Thereafter, our activity since 1993 will be described. At the end of 2004, we had carried out 713 cycles for 319 patients for 54 different indications, leading to 159 (22 %) clinical pregnancies. The ESHRE PGD Consortium, of which I am chairperson, has been collating data on PGD from PGD centres from the whole world. This has led to the publication of four reports that are considered widely as important documents, as well as a comprehensive set of guidelines. Finally, there is the aspect of the scientific research ensuing from the PGD programme. The research into the causes of instability of triplet repeats in genetic diseases such as DM1 and Huntington's disease has made significant progress. The embryonic stem cell lab was started up in 2002, and has already succeeded in deriving five new lines, as well as progressing significantly into the research in differentiation to muscle cells and the behaviour of triplet repeats in totipotent stem cells.

ESHRE PGD Consortium data collection V: cycles from January to December 2002 with pregnancy follow-up to October 2003.

The fifth report of the ESHRE PGD Consortium is presented (data collection V). For the first time, the cycle data were collected for one calendar year (2002) in the following October, so that data collection was complete for pregnancies and babies. The data were collected using a Filemaker Pro database and divided into referrals, cycles, pregnancies and babies. There are currently 66 active centres registered with the consortium; however, the data presented here were obtained from 43 centres and included 1603 referrals, 2219 cycles, 485 pregnancies and 382 babies born. The cycle data were divided into preimplantation genetic diagnosis (PGD) for inherited disorders (including chromosome abnormalities, sexing for X-linked disease and monogenic disorders), aneuploidy screening (PGS) and the use of PGD for social sexing. Data collection V is compared with the previous cumulative data collection (I-IV), which comprised 4058 PGD/PGS cycles that reached oocyte retrieval.

ESHRE PGD Consortium 'Best practice guidelines for clinical preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS)'.

Among the many educational materials produced by the European Society of Human Reproduction and Embryology (ESHRE) are guidelines. ESHRE guidelines may be developed for many reasons but their intent is always to promote best quality practices in reproductive medicine. In an era in which preimplantation genetic diagnosis (PGD) has become a reality, we must strive to maintain its efficacy and credibility by offering the safest and most effective treatment available. The dominant motivators for the development of current comprehensive guidelines for best PGD practice were (i) the absence of guidelines and/or regulation for PGD in many countries and (ii) the observation that no consensus exists on many of the clinical and technical aspects of PGD. As a consequence, the ESHRE PGD Consortium undertook to draw up guidelines aimed at giving information, support and guidance to potential, fledgling and established PGD centres. The success of a PGD treatment cycle is the result of great attention to detail. We have strived to provide a similar level of detail in this document and hope that it will assist staff in achieving the best clinical outcome for their patients.