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result(s) for
"Verhoef, Frans"
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Whole-Genome Shotgun Assembly and Analysis of the Genome of Fugu rubripes
by
Zharkikh, Andrey
,
Pruss, Dmitry
,
Chapman, Jarrod
in
Animals
,
Biological and medical sciences
,
Biological Evolution
2002
The compact genome of Fugu rubripes has been sequenced to over 95% coverage, and more than 80% of the assembly is in multigene-sized scaffolds. In this 365-megabase vertebrate genome, repetitive DNA accounts for less than one-sixth of the sequence, and gene loci occupy about one-third of the genome. As with the human genome, gene loci are not evenly distributed, but are clustered into sparse and dense regions. Some \"giant\" genes were observed that had average coding sequence sizes but were spread over genomic lengths significantly larger than those of their human orthologs. Although three-quarters of predicted human proteins have a strong match to Fugu, approximately a quarter of the human proteins had highly diverged from or had no pufferfish homologs, highlighting the extent of protein evolution in the 450 million years since teleosts and mammals diverged. Conserved linkages between Fugu and human genes indicate the preservation of chromosomal segments from the common vertebrate ancestor, but with considerable scrambling of gene order.
Journal Article
Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: a randomised, double blind, controlled trial
by
Schouten, Evert G
,
Verhoef, Petra
,
Katan, Martijn B
in
Aged
,
Alzheimer's disease
,
alzheimers-disease
2007
Low folate and raised homocysteine concentrations in blood are associated with poor cognitive performance in the general population. As part of the FACIT trial to assess the effect of folic acid on markers of atherosclerosis in men and women aged 50–70 years with raised plasma total homocysteine and normal serum vitamin B
12 at screening, we report here the findings for the secondary endpoint: the effect of folic acid supplementation on cognitive performance.
Our randomised, double blind, placebo controlled study took place between November, 1999, and December, 2004, in the Netherlands. We randomly assigned 818 participants 800 μg daily oral folic acid or placebo for 3 years. The effect on cognitive performance was measured as the difference between the two groups in the 3-year change in performance for memory, sensorimotor speed, complex speed, information processing speed, and word fluency. Analysis was by intention-to-treat. This trial is registered with
clinicaltrials.gov with trial number
NCT00110604.
Serum folate concentrations increased by 576% (95% CI 539 to 614) and plasma total homocysteine concentrations decreased by 26% (24 to 28) in participants taking folic acid compared with those taking placebo. The 3-year change in memory (difference in Z scores 0·132, 95% CI 0·032 to 0·233), information processing speed (0·087, 0·016 to 0·158) and sensorimotor speed (0·064, −0·001 to 0·129) were significantly better in the folic acid group than in the placebo group.
Folic acid supplementation for 3 years significantly improved domains of cognitive function that tend to decline with age.
Journal Article
TP53 germline mutation testing in 180 families suspected of Li–Fraumeni syndrome: mutation detection rate and relative frequency of cancers in different familial phenotypes
by
Sijmons, Rolf H
,
Aalfs, Cora M
,
Rookus, Matti A
in
Adult
,
Biological and medical sciences
,
Brain cancer
2010
BackgroundLi–Fraumeni syndrome (LFS) is a rare autosomal dominant cancer predisposition syndrome. Most families fulfilling the classical diagnostic criteria harbour TP53 germline mutations. However, TP53 germline mutations may also occur in less obvious phenotypes. As a result, different criteria are in use to decide which patients qualify for TP53 mutation analysis, including the LFS, Li–Fraumeni-like (LFL) and Chompret criteria. We investigated which criteria for TP53 mutation analysis resulted in the highest mutation detection rate and sensitivity in Dutch families. We describe the tumour spectrum in TP53-positive families and calculated tumour type specific relative risks.MethodA total of 180 Dutch families referred for TP53 mutation analysis were evaluated. Tumour phenotypes were verified by pathology reports or clinical records.ResultsA TP53 germline mutation was identified in 24 families. When the Chompret criteria were used 22/24 mutations were detected (sensitivity 92%, mutation detection rate 21%). In LFS and LFL families 18/24 mutations were found (sensitivity 75%). The two mutations detected outside the ‘Chompret group’ were found in a child with rhabdomyosarcoma and a young woman with breast cancer. In the mutation carriers, in addition to the classical LFS tumour types, colon and pancreatic cancer were also found significantly more often than in the general population.ConclusionWe suggest TP53 mutation testing for all families fulfilling the Chompret criteria. In addition, TP53 mutation testing can be considered in the event of childhood sarcoma and breast cancer before 30 years. In addition to the risk for established LFS tumour types, TP53-positive individuals may also have an elevated risk for pancreatic and colon cancer.
Journal Article
No Effect of Folic Acid Supplementation on Global DNA Methylation in Men and Women with Moderately Elevated Homocysteine
2011
A global loss of cytosine methylation in DNA has been implicated in a wide range of diseases. There is growing evidence that modifications in DNA methylation can be brought about by altering the intake of methyl donors such as folate. We examined whether long-term daily supplementation with 0.8 mg of folic acid would increase global DNA methylation compared with placebo in individuals with elevated plasma homocysteine. We also investigated if these effects were modified by MTHFR C677T genotype. Two hundred sixteen participants out of 818 subjects who had participated in a randomized double-blind placebo-controlled trial were selected, pre-stratified on MTHFR C677T genotype and matched on age and smoking status. They were allocated to receive either folic acid (0.8 mg/d; n = 105) or placebo treatment (n = 111) for three years. Peripheral blood leukocyte DNA methylation and serum and erythrocyte folate were assessed. Global DNA methylation was measured using liquid chromatography-tandem mass spectrometry and expressed as a percentage of 5-methylcytosines versus the total number of cytosine. There was no difference in global DNA methylation between those randomized to folic acid and those in the placebo group (difference = 0.008, 95%CI = -0.05,0.07, P = 0.79). There was also no difference between treatment groups when we stratified for MTHFR C677T genotype (CC, n = 76; CT, n = 70; TT, n = 70), baseline erythrocyte folate status or baseline DNA methylation levels. In moderately hyperhomocysteinemic men and women, long-term folic acid supplementation does not increase global DNA methylation in peripheral blood leukocytes.ClinicalTrials.gov NCT00110604.
Journal Article
Efficacy of iron-fortified whole maize flour on iron status of schoolchildren in Kenya: a randomised controlled trial
by
Mwaniki, David L
,
West, Clive E
,
Andang'o, Pauline EA
in
absorption
,
Anemia
,
Anemia, Iron-Deficiency - blood
2007
Sodium iron edetic acid (NaFeEDTA) might be a more bioavailable source of iron than electrolytic iron, when added to maize flour. We aimed to assess the effect, on children's iron status, of consumption of whole maize flour fortified with iron as NaFeEDTA or electrolytic iron.
516 children, aged 3–8 years, from four schools in Marafa, Kenya, were randomly assigned to four groups. All were given the same amount of porridge five times a week. The porridge for one group was made from unfortified whole maize flour; for the other three groups it was fortified with either high-dose NaFeEDTA (56 mg/kg), low-dose NaFeEDTA (28 mg/kg), or electrolytic iron (56 mg/kg). Concentrations of haemoglobin, plasma ferritin, and transferrin receptor were analysed in samples taken at baseline and at the end of the 5-month intervention. The primary outcome was iron-deficiency anaemia. We analysed data on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov, number NCT00386074.
The prevalence of iron-deficiency anaemia in children given unfortified flour was 10%. Compared with placebo, the prevalence of iron-deficiency anaemia in children given flour fortified with high-dose NaFeEDTA, low-dose NaFeEDTA, and electrolytic iron changed by −89% (95% CI −97% to −49%), −48% (−77% to 20%), and 59% (−18% to 209%), respectively. Consumption of high-dose NaFeEDTA improved all measured iron-status indicators. Low-dose NaFeEDTA decreased the prevalence of iron deficiency but did not noticeably change the prevalence of anaemia. Electrolytic iron did not improve any of these iron-status indicators. Children who were iron-deficient at baseline benefited more from high-dose and low-dose NaFeEDTA than those with sufficient iron at baseline.
Consumption of whole maize flour fortified with NaFeEDTA caused modest, dose-dependent improvements in children's iron status. Fortification with electrolytic iron did not improve their iron status. Therefore, in high-phytate flours, NaFeEDTA is more suitable than electrolytic iron for supplementation of iron in the diet.
Journal Article
Does rapid genetic counseling and testing in newly diagnosed breast cancer patients cause additional psychosocial distress? results from a randomized clinical trial
by
Wevers, Marijke R.
,
Hahn, Daniela E. E.
,
van der Luijt, Rob B.
in
631/208/1516/1510
,
692/699/476
,
692/699/67/1347
2016
Purpose:
Female breast cancer patients carrying a
BRCA1/2
mutation have an increased risk of second primary breast cancer. Rapid genetic counseling and testing (RGCT) before surgery may influence choice of primary surgical treatment. In this article, we report on the psychosocial impact of RGCT.
Methods:
Newly diagnosed breast cancer patients at risk for carrying a
BRCA1/2
mutation were randomized to an intervention group (offer of RGCT) or a usual care control group (ratio 2:1). Psychosocial impact and quality of life were assessed with the Impact of Events Scale, Hospital Anxiety and Depression Scale, Cancer Worry Scale, and the EORTC QLQ-C30 and QLQ-BR23. Assessments took place at study entry and at 6- and 12-month follow-up visits.
Results:
Between 2008 and 2010, 265 patients were recruited into the study. Completeness of follow-up data was more than 90%. Of the 178 women in the intervention group, 177 had genetic counseling, of whom 71 (40%) had
rapid
DNA testing and 59 (33%) received test results before surgery. Intention-to-treat and per-protocol analyses showed no statistically significant differences between groups over time in any of the psychosocial outcomes.
Conclusions:
In this study, RGCT in newly diagnosed breast cancer patients did not have any measurable adverse psychosocial effects.
Genet Med
18
2, 137–144.
Journal Article
Genetic modifiers of CHEK21100delC-associated breast cancer risk
by
Margolin, Sara
,
Dennis, Joe
,
Knight, Julia A.
in
631/208/2489/144/68
,
631/208/726/649
,
692/499
2017
Purpose:
CHEK2
*1100delC is a founder variant in European populations that confers a two- to threefold increased risk of breast cancer (BC). Epidemiologic and family studies have suggested that the risk associated with
CHEK2
*1100delC is modified by other genetic factors in a multiplicative fashion. We have investigated this empirically using data from the Breast Cancer Association Consortium (BCAC).
Methods:
Using genotype data from 39,139 (624 1100delC carriers) BC patients and 40,063 (224) healthy controls from 32 BCAC studies, we analyzed the combined risk effects of
CHEK2
*1100delC and 77 common variants in terms of a polygenic risk score (PRS) and pairwise interaction.
Results:
The PRS conferred odds ratios (OR) of 1.59 (95% CI: 1.21–2.09) per standard deviation for BC for
CHEK2
*1100delC carriers and 1.58 (1.55–1.62) for noncarriers. No evidence of deviation from the multiplicative model was found. The OR for the highest quintile of the PRS was 2.03 (0.86–4.78) for
CHEK2
*1100delC carriers, placing them in the high risk category according to UK NICE guidelines. The OR for the lowest quintile was 0.52 (0.16–1.74), indicating a lifetime risk close to the population average.
Conclusion:
Our results confirm the multiplicative nature of risk effects conferred by
CHEK2
*1100delC and the common susceptibility variants. Furthermore, the PRS could identify carriers at a high lifetime risk for clinical actions.
Genet Med
advance online publication 06 October 2016
Journal Article
Prediction of BRCA1-association in hereditary non-BRCA1/2 breast carcinomas with array-CGH
by
Joosse, Simon A.
,
Tielen, Ivon H. G.
,
Ligtenberg, Marjolijn J.
in
Adult
,
Aged
,
Biomarkers, Tumor - genetics
2009
Background
While new defects in
BRCA1
are still being found, it is unclear whether current breast cancer diagnostics misses many
BRCA1
-associated cases. A reliable test that is able to indicate the involvement of
BRCA1
deficiency in cancer genesis could support decision making in genetic counselling and clinical management. To find
BRCA1
-specific markers and explore the effectiveness of the current diagnostic strategy, we designed a classification method, validated it and examined whether we could find
BRCA1
-like breast tumours in a group of patients initially diagnosed as non-
BRCA1/2
mutation carriers.
Methods
A classifier was built based on array-CGH profiles of 18
BRCA1
-related and 32 control breast tumours, and validated on independent sets of 16
BRCA1
-related and 16 control breast carcinomas. Subsequently, we applied the classifier to 48 breast tumours of patients from Hereditary Breast and Ovarian Cancer (HBOC) families in whom no germ line
BRCA1/BRCA2
mutations were identified.
Results
The classifier showed an accuracy of 91% when applied to the validation sets. In 48 non-
BRCA1/2
patients, only two breast tumours presented a BRCA1-like CGH profile. Additional evidence for
BRCA1
dysfunction was found in one of these tumours.
Conclusion
We here describe the specific chromosomal aberrations in
BRCA1
-related breast carcinomas. We developed a predictive genetic test for
BRCA1
-association and show that
BRCA1
-related tumours can still be identified in HBOC families after routine DNA diagnostics.
Journal Article
Genome-wide association study in BRCA1 mutation carriers identifies Novel Loci associated with breast and ovarian cancer risk
by
Loud, Jennifer T.
,
Pastinen, Tomi
,
Blank, Stephanie V.
in
Biology
,
BRCA1 Protein - genetics
,
BRCA2 Protein - genetics
2013
BRCA1-associated breast and ovarian cancer risks can be modified by common genetic variants. To identify further cancer risk-modifying loci, we performed a multi-stage GWAS of 11,705 BRCA1 carriers (of whom 5,920 were diagnosed with breast and 1,839 were diagnosed with ovarian cancer), with a further replication in an additional sample of 2,646 BRCA1 carriers. We identified a novel breast cancer risk modifier locus at 1q32 for BRCA1 carriers (rs2290854, P = 2.761028, HR = 1.14, 95% CI: 1.09–1.20). In addition, we identified two novel ovarian cancer risk modifier loci: 17q21.31 (rs17631303, P = 1.461028, HR = 1.27, 95% CI: 1.17–1.38) and 4q32.3 (rs4691139, P = 3.461028, HR = 1.20, 95% CI: 1.17–1.38). The 4q32.3 locus was not associated with ovarian cancer risk in the general population or BRCA2 carriers, suggesting a BRCA1-specific association. The 17q21.31 locus was also associated with ovarian cancer risk in 8,211 BRCA2 carriers (P = 261024). These loci may lead to an improved understanding of the etiology of breast and ovarian tumors in BRCA1 carriers. Based on the joint distribution of the known BRCA1 breast cancer risk-modifying loci, we estimated that the breast cancer lifetime risks for the 5% of BRCA1 carriers at lowest risk are 28%–50% compared to 81%–100% for the 5% at highest risk. Similarly, based on the known ovarian cancer risk-modifying loci, the 5% of BRCA1 carriers at lowest risk have an estimated lifetime risk of developing ovarian cancer of 28% or lower, whereas the 5% at highest risk will have a risk of 63% or higher. Such differences in risk may have important implications for risk prediction and clinical management for BRCA1 carriers.
Journal Article