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Genetic Screening (genetic + screening)
Selected AbstractsBook review: Heredity and Hope: The Case for Genetic ScreeningAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2009Mary E. NortonArticle first published online: 30 APR 200 No abstract is available for this article. [source] Diagnosis at dusk: Malignant hypertension and phaeochromocytoma in a 6-year-old girlEMERGENCY MEDICINE AUSTRALASIA, Issue 1 2008John Corcoran Abstract Phaeochromocytoma is a rare catecholamine-secreting tumour that may arise at any age, but is particularly unusual in childhood. The case of a 6-year-old girl who presented with a prolonged history of general malaise, headaches and abdominal pain is reported. On examination, she was noted to have malignant hypertension. Subsequent imaging of the abdomen demonstrated a left adrenal mass, with the diagnosis of phaeochromocytoma being confirmed by serial raised urinary metanephrines. Sympathetic blockade was established prior to definitive surgical treatment, resulting in complete resolution of the patient's symptoms and hypertension. Genetic screening of the family has since identified a previously undocumented missense mutation in the patient's VHL gene. The case raises the importance of routine measurement of blood pressure in all paediatric patients regardless of age, presentation or other factors. [source] Surveillance for Early Detection of Aggressive Parathyroid Disease: Carcinoma and Atypical Adenoma in Familial Isolated Hyperparathyroidism Associated With a Germline HRPT2 Mutation,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2006Thomas G Kelly Abstract Familial hyperparathyroid syndromes involving mutations of HRPT2 (also CDC73), a tumor suppressor, are important to identify because the relatively high incidence of parathyroid malignancy associated with such mutations warrants a specific surveillance strategy. However, there is a dearth of reports describing experience with surveillance and early detection informed by genetic insight into this disorder. Introduction: Familial isolated hyperparathyroidism (FIHP) is a rare cause of parathyroid (PT) tumors without other neoplasms or endocrinopathies. Germline mutations in CASR, MEN1, and rarely, HRPT2 have been identified in kindreds with FIHP. HRPT2 mutations may be enriched in FIHP families with PT carcinoma, underscoring the importance of identifying causative mutations. Materials and Methods: A 13-year-old boy, whose father had died of PT carcinoma, developed primary hyperparathyroidism. A left superior PT mass was identified by ultrasonography and removed surgically. Aggressive histological features of the boy's tumor included fibrous trabeculae, mitoses, and microscopic capsular infiltration. Two years later, under close biochemical surveillance, primary hyperparathyroidism recurred 5 months after documentation of normocalcemia and normal parathyroid status. Ultrasound and MRI identified a newly enlarged right superior PT gland but indicated no recurrent disease in the left neck. Histologic features typical of a benign adenoma were evident after surgical extirpation of the gland. Results: Leukocyte DNA analysis revealed a frameshift mutation in exon 2 of HRPT2. The initial tumor manifested the expected germline HRPT2 mutation, plus a distinct somatic frameshift mutation, consistent with the Knudson "two hit" concept of biallelic inactivation of a classic tumor suppressor gene. Genetic screening of the patient's 7 asymptomatic and previously normocalcemic siblings revealed three with the same germline HRPT2 mutation. One of the siblings newly identified as mutation-positive was noted to be hypercalcemic at the time of the genetic screening. He was found to have a PT adenoma with aggressive features. Two of the five children of another mutation-positive sibling also carry the same HRPT2 mutation. Conclusions: Despite the reported rarity of HRPT2 mutations in FIHP, a personal or family history of PT carcinoma in FIHP mandates serious consideration of germline HRPT2 mutation status. This information can be used in diagnostic and management considerations, leading to early detection and removal of potentially malignant parathyroid tumors. [source] Novel MEN1 germline mutations in Brazilian families with multiple endocrine neoplasia type 1CLINICAL ENDOCRINOLOGY, Issue 3 2007Rodrigo A. Toledo Summary Objective, To characterize clinical features and identify MEN1 germline mutations in Brazilian families with multiple endocrine neoplasia type 1 (MEN1). Settings, Non-profit academic centre. Patients, Fourteen Brazilian families with MEN1 and 141 at-risk relatives. Results, We identified 12 different MEN1 disease-causing mutations, seven of them previously unreported: 308delC; 375del21; 549A>T (I147F); 1243delA; 1348T>G (L413R); 1351T>C (L414P) and 1523G>T (W471C). Families with the recurrent mutations 360delTCTA and L413R were shown to be unrelated by mitochondrial-DNA and Y-chromosome haplotype analyses. Most of the MEN1 single point mutations involved evolutionarily conserved residues, whereas most of the deletion/frameshift changes occurred in GC-rich repetitive regions. Genetic screening of 141 at-risk family members identified 38 MEN1 mutation carriers, 37 (97·4%) of whom had at least one major MEN1-related tumour upon clinical investigation. Conclusions, High frequencies of MEN1 gene mutations were detected in Brazilian families with MEN1, including seven new genetic mutations that are predicted to cause inactivation of the MEN1 tumour suppressor gene. Our data underscore the need to implement a systematic MEN1 screening programme in Brazil. [source] CE combined with rolling circle amplification for sensitive DNA detectionELECTROPHORESIS, Issue 2 2008Ni Li Abstract Here we describe an assay which combines CE with rolling circle amplification (RCA) for sensitive DNA detection and quantification. RCA is an isothermal DNA replication technique that generates a long ssDNA with tandem repeats. It requires simpler temperature control in reaction and offers higher sequence specificity and greater quantitation capability compared to other amplification technologies. In this study, RCA amplified the DNA target via a circular template, and the product was digested into monomers for CE analysis. Less than 2,fmol of the DNA target could easily be detected using this RCA-CE assay and the assay has a dynamic range of two orders of magnitudes. Moreover, simultaneous detection of both the target DNA and the internal standard was achieved by designing two padlock probes with different sizes, which could significantly improve the quantification accuracy. The RCA-CE assay is easy to perform, readily adaptable for detection of multiple targets because of the high resolution power of CE, and is compatible with other applications employing RCA as a signal amplification tool. Additionally, this assay can be used with a capillary array system to perform sensitive, high-throughput genetic screening. [source] Multiple genetic tests for susceptibility to smoking do not outperform simple family historyADDICTION, Issue 1 2009Coral E. Gartner ABSTRACT Aims To evaluate the utility of using predictive genetic screening of the population for susceptibility to smoking. Methods The results of meta-analyses of genetic association studies of smoking behaviour were used to create simulated data sets using Monte Carlo methods. The ability of the genetic tests to screen for smoking was assessed using receiver operator characteristic curve analysis. The result was compared to prediction using simple family history information. To identify the circumstances in which predictive genetic testing would potentially justify screening we simulated tests using larger numbers of alleles (10, 15 and 20) that varied in prevalence from 10 to 50% and in strength of association [relative risks (RRs) of 1.2,2.1]. Results A test based on the RRs and prevalence of five susceptibility alleles derived from meta-analyses of genetic association studies of smoking performed similarly to chance and no better than the prediction based on simple family history. Increasing the number of alleles from five to 20 improved the predictive ability of genetic screening only modestly when using genes with the effect sizes reported to date. Conclusions This panel of genetic tests would be unsuitable for population screening. This situation is unlikely to be improved upon by screening based on more genetic tests. Given the similarity with associations found for other polygenic conditions, our results also suggest that using multiple genes to screen the general population for genetic susceptibility to polygenic disorders will be of limited utility. [source] Screening for the BRCA1-ins6kbEx13 mutation: potential for misdiagnosis,,HUMAN MUTATION, Issue 5 2007Susan J Ramus Abstract Misdiagnosis of a germline mutation associated with an inherited disease syndrome can have serious implications for the clinical management of patients. A false negative diagnosis (mutation missed by genetic screening) limits decision making about intervention strategies within families. More serious is the consequence of a false positive diagnosis (genetic test suggesting a mutation is present when it is not). This could lead to an individual, falsely diagnosed as a mutation carrier, undergoing unnecessary clinical intervention, possibly involving risk-reducing surgery. As part of screening 283 ovarian cancer families for BRCA1 mutations, we used two different methods (mutation specific PCR and multiplex ligation-dependant probe amplification) to screen for a known rearrangement mutation L78833.1:g.44369_50449dup (ins6kbEx13). We found false positive and false negative results in several families. We then tested 61 known carriers or non-carriers from an epidemiological study of BRCA1 and BRCA2 mutation carriers (the EMBRACE study). These data highlight the need for caution when interpreting analyses of the ins6kbEx13 mutation and similar mutations, where characterising the exact sequence alteration for a deleterious mutation is not a part of the routine genetic test. © 2007 Wiley-Liss, Inc. [source] Comprehensive survey of mutations in RP2 and RPGR in patients affected with distinct retinal dystrophies: genotype,phenotype correlations and impact on genetic counseling,,HUMAN MUTATION, Issue 1 2007Valérie Pelletier Abstract X-linked forms of retinitis pigmentosa (RP) (XLRP) account for 10 to 20% of families with RP and are mainly accounted for by mutations in the RP2 or RP GTPase regulator (RPGR) genes. We report the screening of these genes in a cohort of 127 French family comprising: 1) 93 familial cases of RP suggesting X-linked inheritance, including 48 out of 93 families with expression in females but no male to male transmission; 2) seven male sibships of RP; 3) 25 sporadic male cases of RP; and 4) two cone dystrophies (COD). A total of 5 out of the 93 RP families excluded linkage to the RP2 and RP3 loci and were removed form the cohort. A total of 14 RP2 mutations, 12 of which are novel, were identified in 14 out of 88 familial cases of RP and 1 out of 25 sporadic male case (4%). In 13 out of 14 of the familial cases, no expression of the disease was noted in females, while in 1 out of 14 families one woman developed RP in the third decade. A total of 42 RPGR mutations, 26 of which were novel, were identified in 80 families, including: 69 out of 88 familial cases (78.4%); 2 out of 7 male sibship (28.6%); 8 out of 25 sporadic male cases (32.0%); and 1 out of 2 COD. No expression of the disease was noted in females in 41 out of 69 familial cases (59.4%), while at least one severely affected woman was recognized in 28 out of 69 families (40.6%). The frequency of RP2 and RPGR mutations in familial cases of RP suggestive of X-linked transmission are in accordance to that reported elsewhere (RP2: 15.9% vs. 6,20%; RPGR: 78.4% vs. 55,90%). Interestingly, about 30% of male sporadic cases and 30% of male sibships of RP carried RP2 or RPGR mutations, confirming the pertinence of the genetic screening of XLRP genes in male patients affected with RP commencing in the first decade and leading to profound visual impairment before the age of 30 years. Hum Mutat 28(1), 81,91, 2007. © 2006 Wiley-Liss, Inc. [source] BRCA1 and BRCA2 germline mutations in Korean patients with sporadic breast cancer,,HUMAN MUTATION, Issue 4 2004Jae Hong Seo Abstract In order to evaluate the role of BRCA1 and BRCA2 germline mutations in Korean patients with sporadic breast cancer, 97 patients with sporadic breast cancer were analyzed for mutations in the BRCA1 and BRCA2 coding regions, by using a combination of fluorescent-conformation sensitive gel electrophoresis (F-CSGE) and direct sequencing. Fifty-five distinct sequence variants were detected, which included three pathogenic truncating mutations, 15 missense mutations, 16 polymorphisms, and 21 intronic variants. Twenty-six of these variants have never been previously reported and may be of Korean-specific origin. Two pathogenic BRCA1 mutations (c.922_924delinsT, c.5445G>A) and one pathogenic BRCA2 mutation (c.2259delT) were observed, and two of these (BRCA1 c.5445G>A and BRCA2 c.2259delT) are novel. The total prevalence of germline pathogenic mutations in BRCA1 and/or BRCA2 in Korean sporadic breast cancer is estimated to be about 3.1%. Considering that the majority of breast cancer cases are sporadic, the present study will be helpful in the evaluation of the need for the genetic screening of germline BRCA mutations in sporadic breast cancer patients. Further study using a larger sample size is required to determine the merits of genetic diagnosis and counseling in breast cancer patients. © 2004 Wiley-Liss, Inc. [source] Surveillance for Early Detection of Aggressive Parathyroid Disease: Carcinoma and Atypical Adenoma in Familial Isolated Hyperparathyroidism Associated With a Germline HRPT2 Mutation,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2006Thomas G Kelly Abstract Familial hyperparathyroid syndromes involving mutations of HRPT2 (also CDC73), a tumor suppressor, are important to identify because the relatively high incidence of parathyroid malignancy associated with such mutations warrants a specific surveillance strategy. However, there is a dearth of reports describing experience with surveillance and early detection informed by genetic insight into this disorder. Introduction: Familial isolated hyperparathyroidism (FIHP) is a rare cause of parathyroid (PT) tumors without other neoplasms or endocrinopathies. Germline mutations in CASR, MEN1, and rarely, HRPT2 have been identified in kindreds with FIHP. HRPT2 mutations may be enriched in FIHP families with PT carcinoma, underscoring the importance of identifying causative mutations. Materials and Methods: A 13-year-old boy, whose father had died of PT carcinoma, developed primary hyperparathyroidism. A left superior PT mass was identified by ultrasonography and removed surgically. Aggressive histological features of the boy's tumor included fibrous trabeculae, mitoses, and microscopic capsular infiltration. Two years later, under close biochemical surveillance, primary hyperparathyroidism recurred 5 months after documentation of normocalcemia and normal parathyroid status. Ultrasound and MRI identified a newly enlarged right superior PT gland but indicated no recurrent disease in the left neck. Histologic features typical of a benign adenoma were evident after surgical extirpation of the gland. Results: Leukocyte DNA analysis revealed a frameshift mutation in exon 2 of HRPT2. The initial tumor manifested the expected germline HRPT2 mutation, plus a distinct somatic frameshift mutation, consistent with the Knudson "two hit" concept of biallelic inactivation of a classic tumor suppressor gene. Genetic screening of the patient's 7 asymptomatic and previously normocalcemic siblings revealed three with the same germline HRPT2 mutation. One of the siblings newly identified as mutation-positive was noted to be hypercalcemic at the time of the genetic screening. He was found to have a PT adenoma with aggressive features. Two of the five children of another mutation-positive sibling also carry the same HRPT2 mutation. Conclusions: Despite the reported rarity of HRPT2 mutations in FIHP, a personal or family history of PT carcinoma in FIHP mandates serious consideration of germline HRPT2 mutation status. This information can be used in diagnostic and management considerations, leading to early detection and removal of potentially malignant parathyroid tumors. [source] Genetic testing for HFE hemochromatosis in Australia: The value of testing relatives of simple heterozygotesJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 7 2002JULEEN A CAVANAUGH AbstractBackground : It is unclear whether screening of relatives of C282Y and H63D heterozygotes (other than compound heterozygotes) for hemochromatosis will detect sufficient numbers of cases to justify introduction of this screening strategy. Methods : Conditional probabilities were determined using published Australian allele frequencies and penetrance data to determine the detection rate of hemochromatosis by testing the siblings and offspring of heterozygotes (subjects with only one HFE mutation). Results : The number of individuals who are at risk of developing increased body iron stores because of HFE mutations is substantially higher (1 in 80) than previously estimated. In addition, 33% of the Australian population are heterozygous for either C282Y or H63D. Based on population estimates, the relative risk to the offspring of C282Y and H63D heterozygotes of developing increased iron stores is 4.1 and 1.5, respectively, while the relative risk to each sibling is 2.3 and 1, respectively. The risk of developing clinical features of hemochromatosis or hepatic fibrosis is likely to be substantially lower. Conclusions : Although the detection rate from testing the families of unaffected heterozygotes is low, this can be justified as a clinically useful screening strategy. At the present time this strategy should be restricted to first-degree relatives of heterozygotes. Further studies are recommended to determine if cascade genetic screening is a cost-effective alternative to general population screening. © 2002 Blackwell Publishing Asia Pty Ltd [source] Human herpesvirus-8 infection in pregnancy and labor: Lack of evidence of vertical transmissionJOURNAL OF MEDICAL VIROLOGY, Issue 3 2004Loredana Sarmati Abstract To investigate whether vertical transmission of the human herpesvirus 8 (HHV-8) may occur during pregnancy or at delivery, we enrolled 295 women recruited attending the Division of Obstetrics and Gynecology of a University Teaching of Rome Tor Vergata, S. Eugenio Hospital. The study population was divided in two groups: 245 pregnant women who underwent amniocentesis for genetic screening at 16,18 weeks gestation (group 1) and 50 women at the childbirth (group 2). Maternal blood was obtained from all women. Amniotic fluid (group 1) and cord blood (group 2) were obtained at midtrimester and at delivery, respectively. The presence of anti-HHV-8 antibodies in serum samples was investigated by an immunfluorescence assay. All amniotic fluids, maternal blood, and cord blood samples from HHV-8 seropositive women were tested for the presence of HHV-8 DNA sequences by the polymerase chain reaction. Thirty women, 27 of the group 1 and three of the group 2, were found to have anti-HHV-8 antibodies. Two neonates of the three seropositive mothers of the group 2 had anti-HHV-8 antibodies in cord blood. HHV-8 DNA sequences were detected in the blood of one woman of the group 2. None of the amniotic fluid and cord blood samples had detectable HHV-8 DNA sequences. This study suggests that vertical transmission of HHV-8 is unlikely or, at least, very rare. J. Med. Virol. 72:462,466, 2004. © 2004 Wiley-Liss, Inc. [source] Primary adrenal insufficiency in childhood and adolescence: Advances in diagnosis and managementJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 11 2004PJ Simm Objectives: Primary adrenal insufficiency occurring in childhood and adolescence is due to abnormalities of gland development, gland responsiveness, and steroid biosynthesis or target organ response. Causes include autoimmune Addison's disease, tuberculosis, HIV, adrenoleukodystrophy, adrenal hypoplasia congenita and syndromes including triple A and IMAGe. We aimed to define the causes of adrenal insufficiency for a cohort of children in Melbourne. Methods: We reviewed the frequency and variety of presentation of primary adrenal insufficiency to the Royal Children's Hospital over the past 10 years through an audit of patient records, collating demographic information, presentation and investigations. Results: Sixteen cases (13 male, 3 female) of primary adrenal insufficiency were diagnosed at this hospital between January 1993 and July 2003. Median age at presentation was 7.7 years (range: birth to 14.8 years). Symptoms at presentation included weakness, increased pigmentation, abdominal pain, nausea, developmental delay or a reduction in school performance. Four patients presented with adrenal crisis. Median adrenocorticotrophic hormone (ACTH) at diagnosis was 246 pmol/L (range 30,969 pmol/L). Autoantibodies were positive in five patients. Five patients had elevation of very long chain fatty acids. Five patients were diagnosed with autoimmune adrenal insufficiency, five with adrenal hypoplasia congenita, five with adrenoleukodystrophy and one with IMAGe syndrome. Conclusions: A high index of suspicion results in earlier detection and possible prevention of adrenal crisis with a reduction in associated morbidities. Definitive diagnosis is now possible for almost all cases of primary adrenal insufficiency using technologies for screening autoimmunity, adrenoleukodystrophy (ALD) and genetic screening. [source] Asymptomatic individuals at genetic risk of haemochromatosis take appropriate steps to prevent disease related to iron overloadLIVER INTERNATIONAL, Issue 3 2008Katrina J. Allen Abstract Background/Aims: If community screening for hereditary haemochromatosis is to be considered, compliance with preventative measures and absence of significant psychological morbidity must be demonstrated. Methods: Workplace screening for the HFE C282Y mutation and then clinical care for C282Y homozygotes was instituted. Data were collected on understanding of test results, perceived health status and anxiety for C282Y homozygotes compared with controls. Uptake of clinical care, compliance and response to treatment and changes in diet were monitored for up to 4 years for C282Y homozygotes. Results: After 11 307 individuals were screened, 40/47 (85%) newly identified C282Y homozygotes completed questionnaires 12 months after diagnosis compared with 79/126 (63%) of controls. Significantly more C282Y homozygotes correctly remembered their test result compared with controls (95 vs 51%, P<0.0001). No significant difference in perceived health status was observed within or between the two groups at 12 months compared with baseline. Anxiety levels decreased significantly for C282Y homozygotes at 12 months compared with before testing (P<0.05). Forty-five of the 47 (95.8%) C282Y homozygotes accessed clinical care for at least 12 months. All 22 participants requiring therapeutic venesection complied with treatment for at least 12 months (range 12,47 months). Conclusion: Individuals at a high genetic risk of developing haemochromatosis use clinical services appropriately, maintain their health and are not ,worried well'. Population genetic screening for haemochromatosis can be conducted in the work place in a way that is acceptable and beneficial to participants. [source] Species discovery in marine planktonic invertebrates through global molecular screeningMOLECULAR ECOLOGY, Issue 5 2010ERICA GOETZE Abstract Species discovery through large-scale sampling of mitochondrial diversity, as advocated under DNA barcoding, has been widely criticized. Two of the primary weaknesses of this approach, the use of a single gene marker for species delineation and the possible co-amplification of nuclear pseudogenes, can be circumvented through incorporation of multiple data sources. Here I show that for taxonomic groups with poorly characterized systematics, large-scale genetic screening using a mitochondrial DNA marker can be a very effective approach to species discovery. Global sampling (120 locations) of 1295 individuals of 22 described species of eucalanid copepods identified 15 novel evolutionarily significant units (ESUs) within this marine holoplanktonic family. Species limits were tested under reciprocal monophyly at the mitochondrial (mt) gene 16S rRNA, and 13 of 15 lineages were reciprocally monophyletic under three phylogenetic inference methods. Five of these mitochondrial ESUs also received moderate support for reciprocal monophyly at the independently-inherited nuclear gene, internal transcribed spacer 2 (ITS2). Additional support for the utility of mt DNA as a proxy for species boundaries in this taxon is discussed, including results from related morphological and biogeographic studies. Minimal overlap of intra-ESU and inter-ESU 16S rRNA genetic distances was observed, suggesting that this mt marker performs well for species discovery via molecular screening. Sampling coverage required for the discovery of new ESUs was found to be in the range of >50 individuals/species, well above the sampling intensity of most current DNA Barcoding studies. Large-scale genetic screening can provide critical first data on the presence of cryptic species, and should be used as an approach to generate systematic hypotheses in groups with incomplete taxonomies. [source] Parent responses to participation in genetic screening for diabetes riskPEDIATRIC DIABETES, Issue 4 2004Barbro Lernmark Abstract:, Screening for type 1 diabetes (T1DM) risk in newborns has little negative emotional impact on mothers. In this study, the impact on the mother and the father was evaluated both in the general population and in families with diabetes. All parents with a newborn in Skåne, Sweden, were invited to a screening for T1DM risk in their children (the Diabetes Prediction in Skåne (DiPiS)). Blood was obtained at delivery from the mother and the child. When the child was 2 months old, parents gave written consent and filled out questionnaires, but were not informed about the genetic risk. Of the 10 538 invited families, 6831 (64.8%) consented and 806 (7.7%) declined participation. Five questions addressing both parents were filled out by 6676 (63.4%) mothers and 6099 (57.8%) fathers. In 146/6676 (2.2%) families, one family member had diabetes (D-families). Participation in DiPiS did not affect most parents and the majority was satisfied with the information. The majority of parents (28.9%) were reassured and only 1.1% (140/12 670) reported increased worries because of participation, compared to 2.8% of the mothers in D-families. Parents in D-families more often ascribed diabetes risk to their child as well as the risk being higher. Mothers and fathers differed in their answers on four of the five study questions, with mothers being more satisfied with the information, reporting more knowledge of diabetes, estimating lower risk of their child to get diabetes, but reporting more worries of possible future chronic disease in the child. Parents with lower education, being born abroad, or being younger who reported worries of chronic disease in the child were also reassured by participation in the study. These results confirm that screening for T1DM risk in newborns does not create worries in most parents, but stress that fathers differ from mothers in opinions and reactions, that parents' reactions are affected by diabetes in the family, and that demographic factors might be important for the parents' reports. [source] Next generation of elevated [CO2] experiments with crops: a critical investment for feeding the future worldPLANT CELL & ENVIRONMENT, Issue 9 2008ELIZABETH A. AINSWORTH ABSTRACT A rising global population and demand for protein-rich diets are increasing pressure to maximize agricultural productivity. Rising atmospheric [CO2] is altering global temperature and precipitation patterns, which challenges agricultural productivity. While rising [CO2] provides a unique opportunity to increase the productivity of C3 crops, average yield stimulation observed to date is well below potential gains. Thus, there is room for improving productivity. However, only a fraction of available germplasm of crops has been tested for CO2 responsiveness. Yield is a complex phenotypic trait determined by the interactions of a genotype with the environment. Selection of promising genotypes and characterization of response mechanisms will only be effective if crop improvement and systems biology approaches are closely linked to production environments, that is, on the farm within major growing regions. Free air CO2 enrichment (FACE) experiments can provide the platform upon which to conduct genetic screening and elucidate the inheritance and mechanisms that underlie genotypic differences in productivity under elevated [CO2]. We propose a new generation of large-scale, low-cost per unit area FACE experiments to identify the most CO2 -responsive genotypes and provide starting lines for future breeding programmes. This is necessary if we are to realize the potential for yield gains in the future. [source] Moving up the slippery slope: Mandated genetic screening on Cyprus,AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 1 2009Ruth Schwartz Cowan Abstract Many social scientists and bioethicists have argued that genetic screening is a new form of eugenics. Examination of the development of the quasi-mandated screening program for ,-thalassemia in the Republic of Cyprus (1970,1984) demonstrates that there is nothing eugenic about modern genetic screening practices. The Cypriot screening program involves mandated premarital carrier screening, voluntary prenatal diagnosis (originally through fetoscopy, now through CVS), and voluntary termination of afflicted pregnancies,all at public expense. In the Republic of Cyprus, the mandating agency for genetic screening is the established church, so this examination also demonstrates that religious authorities with profound objections to abortion can balance that moral precept against others, such as the imperative to reduce suffering that sometimes conflict with it. © 2009 Wiley-Liss, Inc. [source] FISH analysis of 15 chromosomes in human day 4 and 5 preimplantation embryos: the added value of extended aneuploidy detectionPRENATAL DIAGNOSIS, Issue 1 2007E. B. Baart Abstract Objective Screening for an increased number of chromosomes may improve the detection of abnormal embryos and thus contribute to the capability of preimplantation genetic screening (PGS) to detect the embryo(s) for transfer in IVF with the best chance for a healthy child. Good-quality day 4 and 5 embryos were analyzed after cryopreservation for the nine chromosomes mostly recommended for screening (13, 14, 15, 16, 18, 21, 22, X and Y), next to six additional chromosomes which are less well studied in this context (1, 2, 7, 6, 10 and 17). Method The copy numbers of 15 chromosomes were investigated by fluorescence in situ hybridization (FISH) in three consecutive rounds. The proportion of aneuploid and mosaic embryos was determined and compared in retrospect to results in case only the recommended probe set had been analyzed. Results A total of 52 embryos from 29 infertile women were analyzed. Screening the embryos for six additional chromosomes increased the proportion of abnormal embryos from 67 to 81% (P = 0.03), owing to an increase in mosaic embryos. Conclusion All but one of the meiotic aneuploidies found in this study would have been detected by the probe set most frequently used in PGS clinics. However, aneuploid cell lines originating from mitotic errors could be detected for almost all chromosomes, so screening of six additional chromosomes mainly increased the proportion of mosaic embryos. The added value of screening for six additional chromosomes in PGS for clinical practice will remain undetermined as long as the fate of mosaic embryos after transfer is unclear. Copyright © 2007 John Wiley & Sons, Ltd. [source] Mutations of genes in synthesis of the carotenoid precursors of ABA lead to pre-harvest sprouting and photo-oxidation in riceTHE PLANT JOURNAL, Issue 2 2008Jun Fang Summary Pre-harvest sprouting (PHS) or vivipary in cereals is an important agronomic trait that results in significant economic loss. A considerable number of mutations that cause PHS have been identified in several species. However, relatively few viviparous mutants in rice (Oryza sativa L.) have been reported. To explore the mechanism of PHS in rice, we carried out an extensive genetic screening and identified 12 PHS mutants (phs). Based on their phenotypes, these phs mutants were classified into three groups. Here we characterize in detail one of these groups, which contains mutations in genes encoding major enzymes of the carotenoid biosynthesis pathway, including phytoene desaturase (OsPDS), ,-carotene desaturase (OsZDS), carotenoid isomerase (OsCRTISO) and lycopene , -cyclase (,-OsLCY), which are essential for the biosynthesis of carotenoid precursors of ABA. As expected, the amount of ABA was reduced in all four phs mutants compared with that in the wild type. Chlorophyll fluorescence analysis revealed the occurrence of photoinhibition in the photosystem and decreased capacity for eliminating excess energy by thermal dissipation. The greatly increased activities of reactive oxygen species (ROS) scavenging enzymes, and reduced photosystem (PS) II core proteins CP43, CP47 and D1 in leaves of the Oscrtiso/phs3-1mutant and OsLCY RNAi transgenic rice indicated that photo-oxidative damage occurred in PS II, consistent with the accumulation of ROS in these plants. These results suggest that the impairment of carotenoid biosynthesis causes photo-oxidation and ABA-deficiency phenotypes, of which the latter is a major factor controlling the PHS trait in rice. [source] 2161: Development of a next-generation sequencing platform for retinal dystrophies, with LCA and RP as proof of conceptACTA OPHTHALMOLOGICA, Issue 2010F COPPIETERS Purpose Retinal dystrophies represent an emerging group of hereditary disorders that lead to degeneration of the photoreceptors and/or the retinal pigment epithelium, resulting in irreversible blindness. They are genetically complex, with over 200 disease loci identified so far. Current genetic screening consists of microarray analysis (Asper Ophthalmics) for the most recurrent mutations, and subsequent Sanger sequencing. However, the high cost and low throughput of the latter technology limits testing to only the most recurrent genes. This project aims to develop a high throughput and cost-effective platform for screening of all known disease genes for Leber Congenital Amaurosis (LCA) and retinitis pigmentosa (RP), using the next-generation sequencing (NGS) technology. Methods A NGS panel will be developed for all 16 and 47 known LCA and RP genes, respectively, including coding and untranslated regions, regulatory regions and microRNA binding sites. The protocol will consist of the following steps: 1) high throughput primerdesign and qPCR, 2) ligation, 3) shearing and 4) sequencing on the Illumina Genome Analyser IIx (GAIIx). This innovative protocol overcomes the need for short amplicons in order to render short-read sequences by the GAIIx. This sequencing instrument was chosen because of its high capacity, low cost per base and the absence of interpretation problems at homopolymeric regions. Analysis of the variants will be performed using in-house developed and commercial software, which ranks all variants according to their pathogenic potential. Conclusion Using the proposed protocol, comprehensive screening for all known disease genes for LCA and RP will be available for the first time. [source] The ryanodine receptor type 1 gene variants in African American men with exertional rhabdomyolysis and malignant hyperthermia susceptibilityCLINICAL GENETICS, Issue 6 2009N Sambuughin It has been suggested that exertional rhabdomyolysis (ER) and malignant hyperthermia (MH) are related syndromes. We hypothesize that patients with unexplained ER harbor mutations in the ryanodine receptor gene type 1 (RYR1), a primary gene implicated in MH, and therefore ER patients are at increased risk for MH. Although there are reported cases of MH in individuals of African descent, there are no data available on molecular characterization of these patients. We analyzed RYR1 in six, unrelated African American men with unexplained ER, who were subsequently diagnosed as MH susceptible (MHS) by the Caffeine Halothane Contracture Test. Three novel and two variants, previously reported in Caucasian MHS subjects, were found in five studied patients. The novel variants were highly conserved amino acids and were absent among 230 control subjects of various ethnic backgrounds. These results emphasize the importance of performing muscle contracture testing and RYR1 mutation screening in patients with unexplained ER. The MHS-associated variant Ala1352Gly was identified as a polymorphism predominant in individuals of African descent. Our data underscore the need for investigating RYR1 across different ethnic groups and will contribute to interpretation of genetic screening results of individuals at risk for MH. [source] | |||||||||||||