PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Genetic Screen”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1998

Genetic screening and haemoglobinopathies: ethics, politics and practice.

The increasing availability of information on the human genetic makeup presents both individuals and society with difficult decisions. This paper explores the ethical and practical issues raised by genetic screening for sickle cell and thalassaemia major, by examining the emerging tension between allowing people to make informed choices, on the basis of genetic information, and prevention of haemoglobinopathies. Within this broad context, the paper also explores the more practical issues of providing genetic screening for haemoglobinopathies, such as the meaning of counselling and screening for the general population; the psychological and social implications for people identified as carriers; and the organisation and delivery of services. It concludes that screening is not always informed by a commitment to informed decision making.

Anemia, Sickle Cell↗
PubMed2001

Genetic counselling and genetic screening for Alzheimer's disease and other dementias.

Genetic and nongenetic factors have been identified to have roles in the etiology of dementia. Etiologic heterogeneity and genetic heterogeneity are recognized, especially for Alzheimer's disease which is the most common form of dementia. Asymptomatic individuals are increasingly requesting genetic services such as genetic counselling, predictive testing and screening for genetic risk factors. This paper provides an overview of the current knowledge about genetic counselling and genetic screening for dementia as well as guidelines for the physician.

Aged↗
PubMed2006

Genetic screens for mutations affecting development of Xenopus tropicalis.

We present here the results of forward and reverse genetic screens for chemically-induced mutations in Xenopus tropicalis. In our forward genetic screen, we have uncovered 77 candidate phenotypes in diverse organogenesis and differentiation processes. Using a gynogenetic screen design, which minimizes time and husbandry space expenditures, we find that if a phenotype is detected in the gynogenetic F2 of a given F1 female twice, it is highly likely to be a heritable abnormality (29/29 cases). We have also demonstrated the feasibility of reverse genetic approaches for obtaining carriers of mutations in specific genes, and have directly determined an induced mutation rate by sequencing specific exons from a mutagenized population. The Xenopus system, with its well-understood embryology, fate map, and gain-of-function approaches, can now be coupled with efficient loss-of-function genetic strategies for vertebrate functional genomics and developmental genetics.

Animal Diseases↗
PubMed2004

Implementation of HaemScreen, a workplace-based genetic screening program for hemochromatosis.

There is debate as to whether community genetic screening for the mutation(s) causing hereditary hemochromatosis (HH) should be implemented, due to issues including disease penetrance, health economic outcomes, and concerns about community acceptance. Hemochromatosis is a common preventable iron overload disease, due in over 90% of cases to C282Y homozygosity in the HFE gene. We are, therefore, piloting C282Y screening to assess understanding of genetic information and screening acceptability in the workplace setting. In this program, HaemScreen, education was by oral or video presentation in a group setting. C282Y status was assessed by polymerase chain reaction (PCR) and melt-curve analysis on DNA obtained by cheek-brush sampling. Of eligible participants, 5.8% (1.5-15.8%) attended information and screening sessions, of whom 97.7% (5571 individuals) chose to be tested. Twenty-two C282Y (1 : 253) homozygotes were identified and offered clinical follow-up. There were 638 heterozygotes (1 : 8.7). The determinants for participation have been analyzed in terms of the principles outlined in the Health Belief Model. Widespread screening for HH is readily accepted in a workplace setting, and a one-to-many education program is effective. The level of participation varies greatly and the advertizing and session logistics should be adapted to the specific features of each workplace.

Adolescent↗
PubMed1996

Genetic screening for reproductive planning: methodological and conceptual issues in policy analysis.

OBJECTIVES: This paper explores several critical assumptions and methodological issues arising in cost-effectiveness analyses of genetic screening strategies in the reproductive setting. METHODS: Seven issues that arose in the development of a decision analysis of alternative strategies for cystic fibrosis carrier screening are discussed. Each of these issues required a choice in technique. RESULTS: The presentations of these analyses frequently mask underlying assumptions and methodological choices. Often there is no best choice. In the case of genetic screening in the reproductive setting, these underlying issues often touch on deeply felt human values. CONCLUSIONS: Space limitations for published papers often preclude explaining such choices in detail; yet these decisions determine the way the results should be interpreted. Those who develop these analyses need to make sure that the implications of important assumptions are understood by the clinicians who will use them. At the same time, clinicians need to enhance their understanding of what these models truly mean and how they address underlying clinical, ethical, and economic issues.

Cystic Fibrosis↗
PubMed1990

A genetic screen to identify variants of bovine pancreatic trypsin inhibitor with altered folding energetics.

A genetic screening procedure has been developed to identify mutant forms of bovine pancreatic trypsin inhibitor (BPTI) that can fold to an active conformation but are inactivated more rapidly than the wild-type protein. Small cultures of Escherichia coli containing plasmids with mutagenized BPTI genes were grown in microtiter plates, lysed, and treated with dithiothreitol (DTT). Under these conditions, unfolding and inactivation of the wild-type protein has a half-time of about 10 hours. Variants of BPTI that are inactivated within 1 hour were identified by adding trypsin and a chromogenic substrate. Approximately 11,000 mutagenized clones were screened in this way and 75 clones that produce proteins that can fold but are inactivated by DTT were isolated. The genes coding for 68 "DTT-sensitive" mutant proteins were sequenced, and 25 different single amino acid substitutions at 15 of the 58 residues of the protein were identified. Most of the altered residues are largely buried in the core of the native wild-type structure and are highly conserved among proteins homologous to BPTI. These results indicate that a large fraction of the sequence of the protein contributes to the kinetic stability of the active conformation, but it also appears that substitutions can be tolerated at most sites without completely preventing folding. Because this genetic screen is based on changes in folding energetics, further studies of the isolated mutants are expected to provide information about the roles of the altered residues in folding and unfolding.

Amino Acid Sequence↗
PubMed2000

A genetic screen for novel behavioral mutations in mice.

A genetic screen using mice was performed to identify dominant loci affecting behavior. Mice were mutagenized with ENU, then bred to examine their G1 offspring for behavioral abnormalities. Potentially mutant G1 pups were screened through a variety of behavioral assays, including tests of learning and memory, sensorimotor gating, fear and anxiety, nociception (pain perception) and locomotor activity. Mice falling outside the normal performance distribution in these tests were considered potential behavioral mutants and were bred for further analysis. Outliers included both animals with very discrete defects and animals with abnormal performance across a range of tests. To date, we have identified two confirmed mutants affecting sensorimotor gating. These results provide further impetus for the use of random mutagenesis screens as a tool for dissecting the genetic basis of brain and behavior.

Alkylating Agents↗
PubMed2003

A genetic screen in Drosophila for metastatic behavior.

A genetic screen was designed in Drosophila to interrogate its genome for mutations sufficient to cause noninvasive tumors of the eye disc to invade neighboring or distant tissues. We found that cooperation between oncogenic RasV12 expression and inactivation of any one of a number of genes affecting cell polarity leads to metastatic behavior, including basement membrane degradation, loss of E-cadherin expression, migration, invasion, and secondary tumor formation. Inactivation of these cell polarity genes cannot drive metastatic behavior alone or in combination with other tumor-initiating alterations. These findings suggest that the oncogenic background of tissues makes a distinct contribution toward metastatic development.

Animals↗
PubMed2001

An exploration of midwives' and obstetricians' knowledge of genetic screening in pregnancy and their perception of appropriate counselling.

OBJECTIVE: to describe levels of knowledge relevant to genetic screening in a sample of midwives and obstetricians in the late 1990s, and to compare these with those found by Smith et al. in London and Wales, and reported in 1994; to describe health professionals' perceptions of an appropriate counselling process relating to genetic screening in comparison with recognised good practice; and to consider links between knowledge and perceptions of the counselling process. DESIGN: a questionnaire study, including responses to a counselling scenario. PARTICIPANTS AND SETTING: responses were obtained from 81 midwives and obstetricians from maternity services in the North West of England. FINDINGS: knowledge about procedures was very good, but knowledge about the probability of genetic abnormality was relatively poor, and respondents overestimated the efficacy and usefulness of tests. These findings were similar to those of Smith et al. (1994), suggesting that they are a good reflection of the national picture. In terms of reported information-giving and counselling practice, there were some respondents who would not check the woman's understanding of her baby's risk of a genetic abnormality, or the risk of a false result. Some respondents would give information based on their own (necessarily limited) experience, rather than national statistics, and give advice based on the choices they themselves would make. These findings reflect earlier, basic research on people's understanding of probabilistic information. IMPLICATIONS: the findings of this study, together with those of earlier work cited, suggest a need for education and training which includes a specific focus on biases in understanding this type of probabilistic information. They also raise the question as to why tests which provide probabilistic data have been introduced without consideration of the known problems in understanding such information.

Attitude of Health Personnel↗
PubMed2000

A bacteriophage lambda-based genetic screen for characterization of the activity and phenotype of the human immunodeficiency virus type 1 protease.

Human immunodeficiency virus type 1 (HIV-1) resistance to antiretroviral drugs is the main cause of patient treatment failure. Despite the problems associated with interpretation of HIV-1 resistance testing, resistance monitoring should help in the rational design of initial or rescue antiretroviral therapies. It has previously been shown that the activity of the HIV-1 protease can be monitored by using a bacteriophage lambda-based genetic assay. This genetic screening system is based on the bacteriophage lambda regulatory circuit in which the viral repressor cI is specifically cleaved to initiate the lysogenic to lytic switch. We have adapted this simple lambda-based genetic assay for the analysis of the activities and phenotypes of different HIV-1 proteases. Lambda phages that encode HIV-1 proteases either from laboratory strains (strain HXB2) or from clinical samples are inhibited in a dose-dependent manner by the HIV-1 protease inhibitors indinavir, ritonavir, saquinavir, and nelfinavir. Distinct susceptibilities to different drugs were also detected among phages that encode HIV-1 proteases carrying different resistance mutations, further demonstrating the specificity of this assay. Differences in proteolytic processing activity can also be directly monitored with this genetic screen system since two phage populations compete in culture with each other until one phage outgrows the other. In summary, we present here a simple, safe, and rapid genetic screening system that may be used to predict the activities and phenotypes of HIV-1 proteases in the course of viral infection and antiretroviral therapy. This assay responds appropriately to well-known HIV-1 protease inhibitors and can be used to search for new protease inhibitors.

Amino Acid Sequence↗
PubMed1995

[Preventive radical surgery of C-cell carcinoma in MEN-II syndrome based on genetic screening].

Between April 1986 and July 1995 121 patients have been operated on for C-cell carcinoma with 70 (57.9%) patients presenting a sporadic type and 51 (42.1%) a hereditary type of disease (46/38% MEN IIa and 5/4.1% MEN IIb). Indication for operation in patients with familial disease (MEN II) was in 9 patients (18%) detection of a mutation in the ret protooncogen (group I), in 27 patients (53%) a pathologic biochemical screening (pentagastrin stimulation) (group II), and in 15 patients (29%) the first manifestation in a family (index) (group III). Distribution of stages showed a stage I (T1 N0 M0) in 8/9 (89%) in group I, in 17/27 (63%) in group II, and in 0/15 in group III. In 8 from 9 patients with genetic indication a multifocal microcarcinoma and in one patient a cell-cell hyperplasia could be demonstrated. Accordingly the rate of curative operations with postoperative normalization of basal and pentagastrin stimulated calcitonin levels was 100% (9/9) in group I, 59% (16/27) in group II, and 7% (1/15) in group III. The mean age was 14 (median 12) years in group I, 26 (median 24) years in group II, and 43 (median 40) years in group III). In patients with presymptomatic screening (genetic and biochemical) a thyroidectomy including lymph node dissection of the central compartment was performed as a standard procedure. Postoperative complication rate showed a recurrent nerve palsy of 0 in group I and 4% in group II and a hypoparathyroidism of 0 in group I and 4% in group II. The detection of a mutation correlated with positive histological findings of the disease in all patients. The prophylactic radical operation on the basis of a genetic screening proved to be a safe procedure with curative intention. The early age of manifestation underlines the importance of the genetic screening and the early indication for operation.

Adolescent↗
PubMed2003

["Screening" in special situations. Assessing predictive genetic screening for hereditary breast and colorectal cancer].

AIMS AND METHODS: The aim of this health technology assessment was to analyse the current scientific and genetic counselling on predictive genetic testing for hereditary breast and colorectal cancer. Predictive genetic testing will be available for several common diseases in the future and questions related to financial issues and quality standards will be raised. This report is based on a systematic/nonsystematic literature search in several databases (e.g. EmBase, Medline, Cochrane Library) and on a specific health technology assessment report (CCOHTA) and review (American Gastroenterological Ass.), respectively. Laboratory test methods, early detection methods and the benefit from prophylactic interventions were analysed and social consequences interpreted. BACKGROUND: Breast and colorectal cancer are counted among the most frequently cancer diseases. Most of them are based on random accumulation of risk factors, 5-10% show a familial determination. A hereditary modified gene is responsible for the increased cancer risk. In these families, high tumour frequency, young age at diagnosis and multiple primary tumours are remarkable. RESULTS AND REFLECTION: GENETIC DIAGNOSIS: Sequence analysis is the gold standard. Denaturing high performance liquid chromatography is a quick alternative method. The identification of the responsible gene defect in an affected family member is important. If the test result is positive there is an uncertainty whether the disease will develop or not, when and in which degree, which is founded in the geno-/phenotype correlation. The individual risk estimation is based upon empirical evidence. The test results affect the whole family. PREVENTION/EARLY DETECTION: Currently, primary prevention is possible for familial adenomatous polyposis (celecoxib, prophylactic colectomy) and for hereditary mamma carcinoma (prophylactic mastectomy). The so-called preventive medical check-ups are early detection examinations. The evidence about early detection methods for colorectal cancer is better than for breast cancer. PROPHYLACTIC SURGICAL INTERVENTIONS: Prophylactic mastectomy (PM) reduces the relative breast cancer risk by approximately 90%. The question is if PM has an impact on mortality. The acceptance of PM is culture-dependent. Colectomy can be used as a prophylactic (FAP) and therapeutic method. After surgery, the cancer risk remains high and so early detection examinations are still necessary. EVIDENCE-BASED STATEMENTS: The evidence is often fragmentary and of limited quality. For objective test result presentation information about sensitivity, specificity, positive predictive value, and number needed to screen and treat, respectively, are necessary. REFLECTIONS: New identification of mutations and demand will lead to an increase of predictive genetic counselling and testing. There is a gap between predictive genetic diagnosis and prediction, prevention, early detection and surgical interventions. These circumstances require a basic strategy. Since predictive genetic diagnosis is a very sensitive issue it is important to deal with it carefully in order to avoid inappropriate hopes. Thus, media, experts and politicians need to consider opportunities and limitations in their daily decision-making processes.

Breast Neoplasms↗
PubMed2003

From what should we protect future generations: germ-line therapy or genetic screening?

This paper discusses the issue of whether we have responsibilities to future generations with respect to genetic screening, including for purposes of selective abortion or discard. Future generations have been discussed at length among scholars. The concept of 'Guardian for Future Generations' is tackled and its main criticisms discussed. Whilst germ-line cures, it is argued, can only affect family trees, genetic screening and testing can have wider implications. If asking how this may affect future generations is a legitimate question and since we indeed make retrospective moral judgements, it would be wise to consider that future generations will make the same retrospective judgements on us. Moreover such technologies affect present embryos to which we indeed can be considered to have an obligation.

Biomedical Research↗
PubMed1997

[Risks and benefits of genetic screening: the sickle cell trait as a model in a Brazilian population group]

Population screening of asymptomatic heterozygotes for genetic guidance purposes is a very controversial procedure due to the risk of labeling, discrimination, stigmatization, loss of self-esteem, and invasion of privacy. Effects of genetic counseling supplied to blood donors with the sickle cell trait (AS heterozygotes) were investigated. Ninety-two AS donors were invited by letter to a free, individual orientation session; 66 of them (72%) accepted the invitation. Some 50% of the individuals brought their wives and children for examination, thus allowing identification of several at-risk couples (13%) and children with sickle cell anemia (5%). Six months afterwards 43 AS donors (65%) were reevaluated, whereby it was observed that the information had been well assimilated. The theoretical risks of genetic screening did not appear to be cause for concern in most of the cases examined. However, signs of stigma, labeling, discrimination, loss of self-esteem, and invasion of privacy were evidenced in a few cases.

Journal Article↗
PubMed1979

Genetic screening in Western Australia.

The wider application of genetic screening is described in four Western Australian populations. Counselling with prenatal diagnosis of Down's syndrome was offered to 57 women over the age of 35 years and less than 16 weeks' gestation who attended an antenatal outpatients department. Forty-four women consented to amniocentesis and two affected fetuses were found. Both public and private patients can be screened to detect fetuses with Down's syndrome. In a population of 200 pregnant girls whose infants were intended for adoption, a specially designed family history form aided identification of genetic disorders in 32 families. Counselling was offered to the biological parents, to the adoptive parents, and, prospectively, to the child in later years. The effectiveness of the family history as a screening device is illustrated in this adoption sample. Counselling of parents of 20 decreased malformed infants initiated the genetic counselling clinic in Western Australia and led to subsequent referral of 92 similar cases by the family doctors. It was found that parents who gave birth to malformed infants welcome information and risk figures. Diagnostic screening in a population of 6000 intellectually handicapped individuals yielded 1372 cases (23%) with Mendelian, multifactorial, or chromosomal modes of inheritance. This screening enabled patients with inherited causes for their intellectual handicap to be identified and placed on a register for health planning.

Abortion, Induced↗
PubMed1994

Patient and parental attitudes toward genetic screening and its implications at an adult cystic fibrosis centre.

General population screening for cystic fibrosis carrier status in the United Kingdom would detect 72% of at-risk couples. Proper counselling would allow these couples to make informed reproductive choices, including the possibility of prenatal diagnosis and the termination of an affected pregnancy. However, children with cystic fibrosis born in this decade, given optimum treatment, now have an average life expectancy of 40 years, and there is no unanimity of opinion on how, where, when, or even if, screening should be offered. The purpose of this questionnaire-based study was to examine the attitudes of an adult clinic population who have grown up with cystic fibrosis, and of their parents, towards genetic screening programmes and the controversies and ethical dilemmas surrounding such programmes in cystic fibrosis. Both patients and parents supported prenatal screening (88% and 90%) and the option of terminating an affected pregnancy (68% and 84%). Only 22% of patients and 10% of parents felt that screening should be limited to families with a history of cystic fibrosis, and 19% and 6%, respectively, that prenatal diagnosis should be restricted to those with a previous child with cystic fibrosis. Despite the negative aspects of any screening programme and the acknowledged ethical problems peculiar to cystic fibrosis, the conclusion of our patients and parents who have lived intimately with the illness is that there should be the option of utilising information available from genetic screening for cystic fibrosis to guide reproductive choices. Pilot programmes to define the optimum management of such screening should continue.

Abortion, Therapeutic↗