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At least 19 recordsLinked to original sources
PubMed2001

[First attempts in preimplantation genetic diagnosis: genetic analysis].

Preimplantation genetic diagnosis is a new approach for the prevention of genetic disorders, which provides a healthy pregnancy avoiding the need for its possible termination. The combination of in vitro fertilization techniques and single cell molecular genetic diagnosis allows only unaffected embryos to be selected for transfer to the uterus. It is an acceptable alternative of prenatal diagnosis for certain couples. Here we report our first attempts in the application of fluorescent PCR for sex determination and the detection of the delta-F508 mutation in human blastomeres. We modelled clinical PGD situations as we performed sex determination on 23 preembryos. Sex determination was successful is 20 preembryos (83%). We performed the detection of the delta-F508 mutation on 23 preembryos, which was successful in 20 preembryos (87%). Our experience suggests, that the established fluorescent PCR analysis is a reliable method for PGD, which enables us to apply it for clinical preimplantation genetic diagnosis.

Blastomeres↗
PubMed1999

Clinical impact of molecular genetic diagnosis, genetic counseling, and management of hereditary cancer. Part II: Hereditary nonpolyposis colorectal carcinoma as a model.

Hereditary nonpolyposis colorectal carcinoma (HNPCC) is the most common hereditary form of colorectal carcinoma (CRC) and may account for 5-10% of the total CRC burden. The discovery of DNA mismatch repair (MMR) genes, inclusive of hMSH2, hMLH1, hPMS2, and hMSH6, has enabled the identification of who has and who does not have inordinately increased susceptibility to CRC as well as a litany of extracolonic cancers. Mutation testing has focused on hMSH2 and hMLH1, the most common mutations in HNPCC. The protocol for DNA testing and DNA-based genetic counseling is described in Part I of this study. One hundred ninety-nine bloodline relatives were tested and counseled from five hMLH1 and two hMSH2 families. Their major reason for seeking genetic counseling and DNA testing was to inform their children and other loved ones of their mutation status. Those who sought counseling overestimated their risk for inheriting the mutation and showed a high rate of interest in prophylactic surgery, and many were greatly concerned about insurance discrimination. Knowledge about HNPCC, its molecular genetic diagnosis, surveillance and management opportunities, and genetic counseling implications are still emerging, all in the face of a greater need for physician education regarding all facets of hereditary cancer.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Clinical impact of molecular genetic diagnosis, genetic counseling, and management of hereditary cancer. Part I: Studies of cancer in families.

Hereditary cancer represents approximately 5-10% of the total cancer burden and may account for 60,000 to 120,000 new cancer occurrences this year in the United States. New developments in molecular genetics and the cloning of cancer-prone genes have intensely fueled interest in dealing with hereditary forms of cancer. The authors provide an algorithm that depicts the process for the identification, study, and DNA-based genetic counseling of families being investigated under a research proposal at the Hereditary Cancer Institute of Creighton University School of Medicine. They have studied 56 hereditary nonpolyposis colorectal carcinoma families; in 18 of them, associated genomic mutations have been identified in affected members. DNA-based genetic counseling has been provided for seven of these families. The authors have also evaluated 131 hereditary breast-ovarian carcinoma families. BRCA1 and BRCA2 mutation searches have been performed for 76 of these families; BRCA1 mutations were found in 38 families and BRCA2 mutations in 9. The study of cancer-prone families is a powerful approach to cancer control, particularly when the germ-line mutation is identified in the family and individuals at high risk can be tested, once they provide informed consent, and receive DNA-based genetic counseling. Discovery of the germ-line mutation for cancer proneness provides an unparalleled opportunity to predict patients' life-time risk for cancer of specific anatomic sites, inclusive of a pattern of multiple primaries. Surveillance and management protocols, when melded to the particular syndrome's natural history, can be life-saving.

Clinical Protocols↗
PubMed2000

Pre-implantation genetic diagnosis.

Genetic disorders are a major cause of miscarriage and fetal death. Pre-implantation genetic diagnosis (PGD) can be used to diagnose genetic defects before pregnancy has occurred by creating embryos by IVF, then removing single cells which are genetically analysed using FISH or PCR. Although successful, the techniques have many difficulties because they are highly specialised and at the extreme limit of sensitivity. Newer techniques, however, can rapidly diagnose multiple defects including chromosomal aneuploidy, sex and single gene defects. Embryonic cells can also be DNA fingerprinted to ensure that contamination has not occurred. As embryo screening can increase IVF success rates and decrease miscarriage rates, it will be increasing offered in routine IVF rather than just those patients at high genetic risk. These new, low cost techniques may ultimately allow PGD to be offered to all IVF patients regardless of risk.

Biopsy↗
PubMed2003

[Genetic diagnosis and prenatal genetic diagnosis of fragile X syndrome].

In order to obtain a simple,fast,accurate and low-cost diagnosis method of fragile X syndrome, cytogenetic tests and molecular genetic tests were carried out with direct amplification of (CGG)(n) repeat sequence in 5' terminal of FMR1 gene by PCR and the cDNA sequence of FMR1 by RT-PCR from six mental retardation pedigrees. The proband of pedigree A with high expression of fragile X chromosome(35/273) was detected to be a full mutation patient of fragile X syndrome by the molecular genetic test. There is no expression of fragile X chromosome in the proband and his mother of pedigree B, which was further confirmed as a non-fragile X pedigree by the molecular genetic test. A male foetus of the pedigree C has fragile X chromosome(5/93), but the proband and his mother has no fragile X chromosome. By further detection using molecular genetic test, the male foetus is a full mutation patient of fragile X syndrome, his mother is a permutated carrier, and his brother is a mosaic patient. The proband of pedigree D has high expression of fragile X chromosome (17%), his sister also has expression of fragile X chromosome (5%). By further detection with molecular genetic test, the proband is a full mutation patient of fragile X syndrome,and his sister is a mosaic patient. The probands of pedigrees E and F of the mother were found with suspicions fragile X chromosome, being confirmed as the non-fragile X pedigrees by the molecular genetic test. The conclusion is that the analysis test with direct amplification of 5'j(CGG)n repeat sequence and cDNA sequence in FMR1 gene is simple,fast,low-cost and can be applied in screening, diagnosis and prenatal diagnosis of fragile X syndrome.

English Abstract↗
PubMedDate not supplied

Is intracytoplasmic sperm injection itself an indication to perform preimplantation genetic diagnosis (PGD)? About PGD, invasive prenatal diagnosis and genetic sonography.

Intracytoplasmic sperm injection (ICSI) provides the only sufficient treatment to overcome severe forms of male infertility. However, male infertility is linked to several genetic problems as an increased number of chromosomal aberrations, cystic fibrosis transmembrane conductance regulator gene mutations, Y-chromosome microdeletions, and androgen receptor mutations. Therefore, these couples are at a higher risk of transmitting genetic problems to their offspring compared to the general population. A proposed increased number of gonosomal aberrations in the offspring possibly results from the ICSI technique itself. This led in general to a worldwide agreement to counsel those couples to undergo invasive prenatal diagnosis in order to exclude chromosome abnormalities, especially gonosomal aberrations. In this paper the genetic risks of these couples and the possible implications of ICSI itself are discussed. Preimplantation genetic diagnosis may be considered a procedure of choice in these cases, but substantial ethical problems arise when such a screening is sought. An alternative procedure of prenatal diagnosis in these couples seems to be 'genetic sonography', i.e. high-resolution ultrasound with measurement of nuchal translucency at the end of the first trimester, and detailed fetal evaluation at 18-22 weeks of gestation.

Chromosome Aberrations↗
PubMed2002

Preimplantation genetic diagnosis.

Preimplantation genetic diagnosis is essentially an alternative to prenatal diagnosis, in which genetic testing is performed on embryos before a clinical pregnancy is established. Preimplantation genetic diagnosis has been applied to patients carrying chromosomal rearrangements, such as translocations, in which it has been proven to decrease the number of spontaneous abortions and prevent the birth of children affected with chromosome imbalance. Preimplantation genetic diagnosis techniques have also been applied to increase implantation rates, reduce the incidence of spontaneous abortion and prevent trisomic offspring in women of advanced maternal age undergoing fertility treatment. A third group of patients receiving preimplantation genetic diagnosis are those at risk of transmitting a single gene disorder to their children. The number of monogenic disorders that have been diagnosed in preimplantation embryos has increased each year. Recent protocols have tended to be more complex and more reliable than previous methods, making greater use of multiplex polymerase chain reaction. As well as an expansion in the variety of disorders for which preimplantation genetic diagnosis is offered, new indications have been reported including the use of human leukocyte antigen histocompatibility typing and the application of preimplantation genetic diagnosis to late onset diseases.

Female↗
PubMed1997

Update in preimplantation genetic diagnosis. Age, genetics, and infertility.

PGD has been successfully used for several years. Over 40 babies have been born worldwide by use of these techniques. Unfortunately, a number of misdiagnoses have been made, a distressing consequence of a new frontier. Significant advances have been made to improve the efficiency and accuracy of PCR and FISH. The widespread use of this technology awaits further documentation of safety and accuracy. Other issues must also be addressed. First, the cost-effectiveness of the techniques relative to the traditional alternatives must be evaluated. A number of ethical issues regarding embryo screening must be addressed including what diseases are serious enough to warrant the procedure. Another concern is the use of this technology for nongenetic disorders such as gender selection. Finally, the experimental nature of these procedures must continually be discussed with patients, and long-term follow-up studies must be undertaken. Development of more accurate and less expensive assays coupled with improved IVF success rates may make PGD a more widely used clinical tool. The future awaits these developments.

Age Factors↗
PubMedDate not supplied

Breast cancer genetics: family history, heterogeneity, molecular genetic diagnosis, and genetic counselling.

Between 5% and 10% of breast cancer cases can be traced to primary genetic factors. Before the discovery of the BRCA1 and BRCA2 genes, if a first-degree relative in direct genetic lineage had hereditary breast cancer or hereditary breast-ovarian cancer syndrome, the best estimate of family members' genetic risk for breast cancer was 50%. Now the lifetime cancer destiny of a patient who carries a BRCA1 or BRCA2 germ line mutation can be determined with an extraordinary degree of precision. However, a major concern facing clinicians is how to use this powerful genetic knowledge without harming the patient. This presentation focuses on the need for (a) compilation of a detailed family history of cancer of all anatomic sites; (b) understanding of the natural history of hereditary breast cancer and its heterogeneous forms and the pathobiology of hereditary breast cancer; and (c) preparation for performance of genetic counseling that is based on the results of DNA sequencing to detect genes related to cancer susceptibility. The discussion addresses the advantages of this molecular genetic movement, which include the abilities (a) to predict who is and who is not at inordinately high risk for cancer; (b) to provide opportunities for highly targeted disease surveillance and management; (c) to give patients the information they need to make appropriate long-term decisions about matters such as procreation; and (d) to give genetic counselors the information they need to appreciate the emotions patients may encounter, such as fear, anxiety, and apprehension, and the ordeal of being subjected to discrimination by insurance companies and employers.

Adult↗
PubMed1994

Preimplantation genetic diagnosis.

Preimplantation genetic diagnosis now represents an alternative reproductive option for parents at high risk of having offspring affected with certain genetic diseases. Progress in the past year has included increasing reliability in embryo sexing by both polymerase chain reaction and fluorescent in situ hybridization techniques; delivery of babies free of specific diseases such as cystic fibrosis, Lesch-Nyhan syndrome, and Tay-Sachs disease; and successful development of molecular techniques for detecting common diseases such as fragile-X syndrome. In addition, sperm separation in combination with preimplantation genetic diagnosis appears to be an exciting advance in yielding more in vitro fertilization female embryos for transfer and subsequent pregnancy in families at risk for X-linked diseases. Accumulated world experience can now be reviewed to provide couples considering preimplantation genetic diagnosis with observed pregnancy rates and accuracy of diagnosis.

Blastocyst↗
PubMed2006

Three hundred and thirty cycles of preimplantation genetic diagnosis for serious genetic disease: clinical considerations affecting outcome.

OBJECTIVE: To report on our experience with preimplantation genetic diagnosis (PGD) cycles performed for serious genetic disease in relation to the clinical factors affecting outcome. DESIGN: Retrospective review of data from a single centre. SETTING: Tertiary referral PGD centre in a London teaching hospital. METHODS: The PGD cycles included 172 cycles for chromosome rearrangements, 96 cycles for single-gene disorders and 62 cycles for X-linked disorders. In vitro fertilisation was the preferred method in chromosome rearrangement and X-linked cases, while intra cytoplasmic sperm injection was used in all single-gene disorders. Appropriate in situ hybridisation fluorescence probes were used in chromosome rearrangement and X-linked cases and polymerase chain reaction was used in single-gene disorders. All pregnancies were followed till delivery. MAIN OUTCOME MEASURE: Live birth rate per PGD cycle started. RESULTS: Eighty-six percent of cycles started (283) reached oocyte retrieval and 3743 eggs were collected, of which 2086 fertilised normally (55.7%). Two hundred and fifty cycles (76%) had embryos sutiable for biopsy on day 3 of in vitro culture, 1714 embryos were biopsied, and in 205 cycles (62%), there was at least one unaffected embryo available for transfer, resulting in 90 pregnancies, 68 clinical pregnancies and 58 live birth. The live birth rate was 18% per cycle started, 21% per egg retrieval and 28% per embryo transfer which significantly affected the live birth outcome. Woman age, number of eggs collected and achieving cryopreservation of surplus embryos had no statistically significant effect on treatment outcome. CONCLUSIONS: The live birth outcome of PGD cycles for serious genetic disorder is modest and is affected by the number of embryos genetically suitable for transfer.

Adult↗
PubMed1999

Confirmation of diagnosis in preimplantation genetic diagnosis (PGD) through blastocyst culture: preliminary experience.

Three cases of preimplantation genetic diagnosis (PGD) (two for sexing and one for aneuploidy screening) are presented. Embryo biopsy was performed at day 3 and diagnosis was established with fluorescent in situ hybridization (FISH). Embryos not used for replacement were cultured in sequential media for blastocyst development. Blastocyst rate was 39.3 per cent. Confirmations of diagnosis were established with FISH in blastocysts and arrested embryos. Mosaicism was observed in 7/8 blastocysts (mean number of cells analysed: 55.5) and 5/8 arrested embryos. The percentage of abnormal cells was 17.1 per cent for blastocysts and 54 per cent for arrested embryos. Polypoid cells were observed in 4/8 blastocysts. Confirmation of diagnosis at the blastocyst stage is a useful tool in PGD.

Aneuploidy↗
PubMed1998

Rapid trisomy diagnosis (21, 18, and 13) using fluorescent PCR and short tandem repeats: applications for prenatal diagnosis and preimplantation genetic diagnosis.

PURPOSE AND METHODS: Prenatal diagnosis of fetal trisomies is usually performed by cytogenetic analysis from amniotic fluid. This requires lengthy laboratory procedures and high costs and is unsuitable for large-scale screening of pregnant women. An alternative method, which is rapid and inexpensive and may potentially be suitable for diagnosing trisomies even from single fetal cells, is the fluorescent polymerase chain reaction (F-PCR) using polymorphic small tandem repeats (STRs). RESULTS: In this paper we present data demonstrating that fluorescent PCR amplification of STRs can be used for rapid diagnosis of trisomy 21, trisomy 18, and trisomy 13 and can be successfully applied to both prenatal diagnosis and diagnosis of single cells. This study also reports significant numbers of prenatal diagnoses using quantitative fluorescent PCR. CONCLUSIONS: We believe that further studies of greater numbers of samples will determine the absolute reliability of this technique. These results also provide a model for trisomy diagnosis from single cells using multiple STR markers for either preimplantation genetic diagnosis or, potentially, diagnosis from fetal cells isolated from maternal blood.

Chromosomes, Human↗
PubMed2003

Preimplantation genetic diagnosis for achondroplasia: genetics and gynaecological limits and difficulties.

BACKGROUND: We report the first attempts at preimplantation genetic diagnosis (PGD) and IVF and their accompanying difficulties for achondroplasia (ACH) patients. METHODS: A PGD test was developed using fluorescent single cell PCR on lymphoblasts from patients and controls and from blastomeres from surplus IVF embryos. A specific digestion control based on the use of two fluorochromes was elaborated. Ovarian stimulation and oocyte retrieval were carried out using conventional protocols. RESULTS: We performed 88 single cell tests for which amplification was obtained in 86 (97.7%) single lymphoblasts. Allele drop out (ADO) was observed in two out of 53 (3.7%) heterozygous lymphoblasts. If we combine the results from the blastomere testing from surplus embryos with those from PGD cycles and re-analysis after PGD, we obtained a PCR signal in 84% of cases of which 91% were correctly diagnosed at the G380 locus. A total of six cycles were performed resulting in three embryo transfers. We observed difficulties in ovarian stimulation and oocyte retrieval with affected female patients. No pregnancy was obtained. CONCLUSION: A PGD test for ACH is now available at our centre but our initial practice raises questions on the feasibility of such a test, specially with affected female patients.

Achondroplasia↗
PubMed2001

Clinical application of preimplantation genetic diagnosis.

Preimplantation genetic diagnosis (PGD) is an early alternative to prenatal diagnosis that is suitable for a small group of patients who are at substantial risk of conceiving a pregnancy affected by a known genetic defect. Four centres are licensed to perform PGD in the UK. This article reviews the clinical experience of PGD at the Guy's and St Thomas' Centre for Preimplantation Genetic Diagnosis, now the busiest unit for PGD in the UK, and compares it with information from other centres in Europe. The results from the first 40 cycles of treatment and the 12 pregnancies arising from those cycles are detailed. It is our belief that PGD should be seen as an extension of a clinical genetic service, rather than an arm of assisted conception. Making the distinction between treatment for infertility and prevention of genetic defect as part of genetic service provision may improve access to health service funding for patients deserving of PGD.

Female↗