Morris Fiddler

The clinical application of interphase FISH in prenatal diagnosis.

Fluorescence in situ hybridization (FISH) for five chromosomes (13, 18, 21, X and Y) detected 87 of 107 (81%) of the chromosome aberrations identified by conventional chromosome analysis applied to fetal interphase cells obtained by chorionic villus sampling or amniocentesis. The choice of FISH was solely determined by prospective parents after formal genetic counselling concerning the advantages and disadvantages of FISH analysis. Excluding known familial chromosome aberrations, if FISH analysis revealed normal signals, there was an overall residual risk of 1 in 149 for an undetectable chromosome aberration. This risk varied according to the indication for prenatal diagnosis: 1 in 177 for women of advanced maternal age; 1 in 60 for women at increased risk for Down syndrome based on maternal serum screening; and, 1 in 43 for women whose ultrasound examination revealed fetal anomalies. There were 20 cases of discordance between the FISH results and standard karyotype analysis: four were the outcome of a failure to apply the appropriate FISH probe; 16 were not detectable by the available FISH probes. Of these 16, nine were chromosome abnormalities with clinical significance and seven were familial. If FISH is to become a standard part of prenatal genetic diagnosis, genetic counselling that is sensitive to patient health needs must be based on accurate information about the biological and obstetrical implications of the results of FISH analysis. Copyright

Practice-based competencies for accreditation of and training in graduate programs in genetic counseling.

In January 1996, the American Board of Genetic Counseling (ABGC) adopted 27 practice-based competencies as a standard for assessing the training of graduate students in genetic counseling. These competencies were identified and refined through a collective, narrative process that took place from January through November 1994, and included directors of graduate programs in genetic counseling, ABGC board members and expert consultants. These competencies now form the basis of the document “Requirements for Graduate Programs in Genetic Counseling Seeking Accreditation by the American Board of Genetic Counseling” (American Board of Genetic Counseling, 1996). The competencies are organized into four domains and are presented and discussed in this article.

Genetic assessment following increased nuchal translucency and normal karyotype

The objective of this study was to assess the first formal approach for monitoring genetic/developmental syndromes associated with the presence of an increased nuchal translucency (NT) thickness (>3 mm) in the first trimester of pregnancy.

A case-based approach to the development of practice-based competencies for accreditation of and training in graduate programs in genetic counseling.

The American Board of Genetic Counseling (ABGC) sponsored a consensus development conference with participation from directors of graduate programs in genetic counseling, board members, and expert consultants. Using a collective, narrative, and case-based approach, 27 competencies were identified as embedded in the practice of genetic counseling. These competencies were organized into four domains of skills: Communication; Critical Thinking; Interpersonal, Counseling, and Psychosocial Assessment; and Professional Ethics and Values. The adoption of a competency framework for accreditation has a variety of implications for curriculum design and implementation. We report here the process by which a set of practice-based genetic counseling competencies have been derived; and in an accompanying article, the competencies themselves are provided. We also discuss the application of the competencies to graduate program accreditation as well as some of the implications competency-based standards may have for education and the genetic counseling profession. These guidelines may also serve as a basis for the continuing education of practicing genetic counselors and a performance evaluation tool in the workplace.

The expression of genes in human preimplantation embryos

The study of gene expression in human preimplantation embryos is establishing itself as a necessary dimension of developmental biology and medical genetics. Transcripts identified in human preimplantation embryos include housekeeping genes, transcription and growth factor genes, sex‐determining genes, tissue‐specific genes and novel genes, as well as genes of unknown function. Strategies are being developed which will eventually permit the most sophisticated gene expression studies on single human embryos of co‐ordinated transcription and translational regulation. There is both a need for international co‐operation for the systematic construction of expression maps and a need to establish databases of expression patterns during different stages of human development.

Increased nuchal translucency in the presence of normal chromosomes: what's next?

Purpose of review First trimester screening is presently offered to all pregnant women as a means of prenatal screening for Down syndrome, trisomy 18, and trisomy 13. Nuchal translucency measurement is a fundamental component of the screening protocol. A woman whose fetus’ nuchal translucency is greater than the 95th percentile is also at increased risk for a multiplicity of other adverse pregnancy and pediatric outcomes, and as a consequence, counseling of patients about their testing options and range of pregnancy outcomes has become complex and difficult. Recent findings The increased risk for chromosome abnormalities, congenital heart malformations, and pregnancy loss in the presence of an increased nuchal translucency is well documented. What has not been clearly defined is the incidence of other genetic syndromes, congenital defects, and adverse pregnancy and pediatric outcomes in the presence of increased nuchal translucency. Currently, Noonan syndrome is the only molecular genetic condition that has been shown to have a clear association with the finding of increased nuchal translucency in the first trimester. Summary This article reviews the current literature on outcomes in pregnancies with an increased nuchal translucency and a normal karyotype. We summarize the range of outcomes detected in the first trimester with recommendations for further prenatal testing and counseling of patients.

Assessment of fetal status in multiple gestation pregnancies using interphase FISH

The use of fluorescence in situ hybridization (FISH) for women with multiple gestation pregnancies has been evaluated. Women were referred for chromosome analysis because of advanced maternal age, abnormal ultrasound findings or a positive family history and/or prior to fetal reduction. FISH was successfully applied to all specimens obtained by amniocentesis or chorionic villus sampling (CVS). Based on FISH results, fetal–fetal contamination of specimens following CVS was 11.5% in twin pregnancies and 16% in triplet or higher multiples. FISH detected trisomy 21 in three cases with no false negatives or positives. Whereas FISH may provide rapid and useful assessment of fetal status in decision‐making regarding fetal reduction, the present study also highlighted the obstetrical difficulty of ensuring a sample representative of each fetus following CVS in addition to the possibility of not identifying clinically significant chromosome aberrations using currently available FISH probes. Copyright

The role of the preimplantation geneticist in human cloning.

If human cloning is to become a reality, the preimplantation geneticist must be responsible for determining the indications for undertaking cloning and for establishing the risks and benefits of human cloning. The unresolved issue is whether a compelling argument can be made for cloning a human for therapeutic reasons while outweighing legal, moral and ethical objections. At present, ‘whole person’ cloning does not seem justified under any circumstance, whereas cloning for the replacement of diseased cells, tissues or organ systems, i.e. ‘spare parts’, seems to be a likely, acceptable application of cloning strategies for humans. Copyright

Broadening the scope of scholarship: A suggested framework

Recent work by Ernest Boyer and others has prompted some colleges and universities to reexamine the nature of scholarship among faculty members. Using Boyers categories of scholarly activity, the authors have developed a framework for scholarly contribution that is currently being implemented by faculty at DePaul Universitys School for New Learning. The proposed framework includes assumptions regarding scholarship, expectations for faculty relative to scholarly activity, and definitions and criteria for the four forms of scholarship. The authors offer the framework in the hope that it will stimulate a reexamination of the nature of scholarship at other institutions as well.

Are fetal cells in maternal plasma really there? We think they are

AbstractWe describe a single centrifugation procedure that resulted in the recovery of fetal cells in maternal blood in 77% of normal male pregnancies and in 87.5% of aneuploid pregnancies. There was an average yield of one fetal cell/1,993 maternal cells in normal pregnancies, which increased to one in 994, in aneuploid pregnancies.