Leo P. ten Kate

Deficiency of knowledge of genetics and genetic tests among general practitioners, gynecologists, and pediatricians: A global problem

Purpose: The objective of this study was to assess knowledge of genetics and awareness of genetic tests among Dutch general practitioners (GPs), gynecologists (GYNs), and pediatricians (PEDs), as well as factors influencing their knowledge and awareness.Methods: An anonymous questionnaire inquiry was used, validated with a sample of 52 clinical geneticists (CGs). The study was carried out in primary care (general practice) and secondary care (general and university hospitals) in The Netherlands. A random sample of 200 GPs, 300 GYNs, and 265 PEDs received a questionnaire. In addition, all registered CGs (58) received a questionnaire for validation. In total, 122 GPs, 187 GYNs, 164 PEDs, and 52 CGs returned a completed questionnaire. The main outcome measures were differences in knowledge scores between physicians working in different disciplines and factors influencing these scores.Results: Knowledge scores of GPs (mean 64% correct answers, 61%–66% [95% confidence interval]), GYNs (mean 75% correct answers, 73%–76% [95% confidence interval]), and PEDs (mean 81% correct answers, 79%–82% [95% confidence interval]) were lower than those in the CG validation group (mean 95% correct answers, 94%–96% [95% confidence interval]). The 5th percentile of GPs, GYNs, and PEDs was at approximately 40%, 52% and 62% correct answers, respectively. There was a specific lack of knowledge about DNA testing. In addition to specialty, important factors positively associated with the knowledge scores of nongeneticists are more recent graduation, having taken an elective course in genetics, and providing genetic counseling in their own practice.Conclusion: The overall knowledge levels of genetics in many nongeneticist health care providers show clear deficiencies. This is in line with reports from other countries, showing that these deficiencies are a global problem.

TP53 germline mutation testing in 180 families suspected of Li–Fraumeni syndrome: mutation detection rate and relative frequency of cancers in different familial phenotypes

Background Li–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. Method A total of 180 Dutch families referred for TP53 mutation analysis were evaluated. Tumour phenotypes were verified by pathology reports or clinical records. Results A 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. Conclusion We 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.

Consanguineous marriages, pearls and perils: Geneva International Consanguinity Workshop Report.

Approximately 1.1 billion people currently live in countries where consanguineous marriages are customary, and among them one in every three marriages is between cousins. Opinions diverge between those warning of the possible health risks to offspring and others who highlight the social benefits of consanguineous marriages. A consanguinity study group of international experts and counselors met at the Geneva International Consanguinity Workshop from May 3 2010, to May 7, 2010, to discuss the known and presumptive risks and benefits of close kin marriages and to identify important future areas for research on consanguinity. The group highlighted the importance of evidence-based counseling recommendations for consanguineous marriages and of undertaking both genomic and social research in defining the various influences and outcomes of consanguinity. Technological advances in rapid high-throughput genome sequencing and for the identification of copy number variants by comparative genomic hybridization offer a significant opportunity to identify genotype-phenotype correlations focusing on autozygosity, the hallmark of consanguinity. The ongoing strong preferential culture of close kin marriages in many societies, and among migrant communities in Western countries, merits an equivalently detailed assessment of the social and genetic benefits of consanguinity in future studies.

Are pregnant women making informed choices about prenatal screening

Purpose: Prenatal screening should enable pregnant women to make informed choices. An informed decision is defined as being based on sufficient, relevant information and consistent with the decision makers values. This study aims to assess to what extent pregnant women make informed choices about prenatal screening, and to assess the psychological effects of informed decision-making.Methods: The study sample consisted of 1159 pregnant women who were offered the nuchal translucency measurement or the maternal serum screening test. Level of knowledge, value consistency, informed choice, decisional conflict, satisfaction with decision, and anxiety were measured using questionnaires.Results: Of the participants, 83% were classified as having sufficient knowledge about prenatal screening, 82% made a value-consistent decision to accept or decline prenatal screening, and 68% made an informed decision. Informed choice was associated with more satisfaction with the decision, less decisional conflict (this applied only to test acceptors), but was not associated with less anxiety.Conclusion: Although the rate of informed choice is relatively high, substantial percentages of women making uninformed choices due to insufficient knowledge, value inconsistency, or both, were found. Informed choice appeared to be psychologically beneficial. The present study underlines the importance of achieving informed choice in the context of prenatal screening.

PARENTAL ORIGIN AND GERMLINE MOSAICISM OF DELETIONS AND DUPLICATIONS OF THE DYSTROPHIN GENE - A EUROPEAN STUDY

SummaryKnowledge about the parental origin of new mutations and the occurrence of germline mosaicism is important for estimating recurrence risks in Duchenne (DMD) and Becker muscular dystrophy (BMD). However, there are problems in resolving these issues partly because not all mutations can as yet be directly detected, and additionally because genetic ratios are very sensitive to ascertainment bias. In the present study, therefore, analysis was restricted to currently detectable mutations (deletions and duplications) in particular types of families which tend to be rare. In order to obtain sufficient data we pooled results from 25 European centers. In mothers of affected patients who were the first in their family with a dystrophin gene deletion or duplication, the ratio between the paternal and the maternal origin of this new mutation was 32:49 (binomial test P = 0.075) for DMD. In five BMD families the ratio between paternal and maternal origin of new mutations was 3∶2. Recurrence risk because of maternal germline mosaicism was studied in sisters or subsequent sibs of isolated cases with an apparently new detectable mutation. In 12 out of 59 (0.20; 95% CI 0.10–0.31) transmissions of the risk haplotype the DMD mutation was transmitted as well. No recurrences were found in nine BMD families.

SURVIVAL AND CLINICAL OUTCOME IN PATIENTS WITH CYSTIC-FIBROSIS, WITH OR WITHOUT NEONATAL SCREENING

After an experimental neonatal screening program for cystic fibrosis had been carried out in the Netherlands during 1973 to 1979, a follow-up study to evaluate the effects of neonatal screening was started in 1980. Although before 1980 the management of patients with cystic fibrosis was partly left to local hospitals, from the start of the follow-up program all patients in the study received similar treatment. A cumulative survival rate, calculated with exclusion of the patients with meconium ileus, showed at the age of 11 years a significantly better survival rate (p less than 0.05) for the 19 patients from the screened population (88%) than for the 25 patients from the nonscreened population (60%). Clinical condition was assessed on entry and at the age of 9 years in 16 screened and 20 nonscreened patients. On entry, comparison showed significantly better chest radiograph scores for the screened patients but no other significant differences. At the age of 9 years, after several years of similar treatment for all patients in the study, significantly better clinical (p less than 0.02) and chest radiograph scores (p less than 0.01), lower IgG levels (p less than 0.05), and higher vitamin A levels (p less than 0.01) were observed in the screened patients. Our study results suggest that early diagnosis and appropriate treatment may prevent serious deterioration and death at a young age, and may reduce the extent of early irreversible lung damage in patients with cystic fibrosis.

Deficient knowledge of genetics relevant for daily practice among medical students nearing graduation.

Purpose: The objective of this study was to investigate whether the knowledge of genetics relevant for daily practice among medical students nearing graduation in the Netherlands was sufficient to react appropriately to the change of relevance of genetics in medicine.Methods: A computer examination validated in a group of clinical geneticists, medical students nearing graduation, and nonmedical students. The examination consisted of 215 genetic questions classified by the designers into three categories of relevance: “essential” knowledge (requirement: > 95% correct answers), “desirable” knowledge (requirement: > 60% correct answers), and “too specialized” knowledge (no requirement). To set an independent standard, the questions were also judged by clinical geneticists and nongenetic health care providers in an Angoff procedure. In total, 291 medical students nearing graduation from seven out of the eight medical schools in the Netherlands participated.Results: As expected, the mean score for “essential” knowledge (71.63%, 95% CI 70.74–72.52) was higher than for “desirable” knowledge (55.99%, 95% CI 55.08–56.90); the mean score for “too specialized” knowledge (44.40%, 95% CI 43.19–45.62) was the lowest. According to passing scores set for “essential” knowledge as defined by the designers, the clinical geneticists, and the nongenetic health care providers, only 0%, 26%, and 3%, respectively, of the participants would have passed.Conclusions: Medical students nearing graduation lack genetic knowledge that is essential for daily practice. Therefore, changes should be made in the medical curricula.

Confidence of primary care physicians in their ability to carry out basic medical genetic tasks-a European survey in five countries-Part 1

Western health care systems are facing today increasing movement of genetic knowledge from research labs into clinical practice. This paper reports the results of a survey that addressed the confidence of primary care physicians in their ability to carry out basic medical genetic tasks. The survey was conducted in five countries (France, Germany, The Netherlands, Sweden and the UK). Stratified random samples were drawn from primary care physicians in the five countries representing a sampling frame of 139,579 physicians. Stepwise binary logistic regression procedures were performed to identify the predictor variables for self-reported confidence. Three thousand six hundred eighty-six physicians participated and filled out a self-administered questionnaire. The margin of error for accurate representation of each group of European general practitioners and specialists in the total sample is 2.9% for GP, 2.8% for obstetricians/gynaecologists (OB/GYN) and for paediatricians (PAED) 2.6% (95% confidence level). Confidence in their ability to carry out basic medical genetic tasks is low among participating primary care physicians: 44.2% are not confident, 36.5% somewhat confident, confident or very confident are 19.3%. In each country, those confident/very confident represent less than 33% of the participating physicians. Primary care physicians who report the lowest levels of confidence prove to be those least exposed to medical genetics information and training. Although there are significant differences in the way in which professional education is organised and practice is regulated across European countries, there is a need for a coordinated European effort to improve primary care physicians’ background in medical genetics.

Preconceptional genetic carrier testing and the commercial offer directly-to-consumers.

Recently, a number of commercial companies are offering preconceptional carrier tests directly-to-consumers. This offer raises a number of concerns and issues above and beyond those encountered with preconceptional tests offered within the traditional health care setting. In order to bring some of these issues to light and to initiate dialogue on this topic, this article discusses the following issues: the current offer of preconceptional carrier tests (until the end of 2010) through online commercial companies; the implications for the informed consent procedure and the need for good information; the need for medical supervision and follow-up; and the appropriate use of existing resources. The article concludes with some reflections about the potential sustainability of the offer of preconceptional carrier tests directly-to-consumers.

Birth and population prevalence of Duchenne muscular dystrophy in the Netherlands

SummaryMutations causing Duchenne muscular dystrophy (DMD) have a short survival. Therefore, birth and population prevalence are maintained by new mutations. The present inventory was made to estimate the birth and population prevalence rates of DMD in the Netherlands. Seven methods of case identification were used. Data on 496 definite, probable or possible DMD patients born since 1961, or alive on January 1, 1983, were obtained. Several methods gave an estimated ascertainment of more than 95%. The prevalence rate at birth of DMD was estimated at 23.7×10−5 (1∶4215) male live births (MLB) yearly. The prevalence rate in the male population on January 1, 1983 was 5.4×10−5 (1∶18496). About 1% of the males in this study may have autosomal recessive Duchenne-like muscular dystrophy. Until now there has been no convincing evidence for geographic differences in DMD prevalence at birth. A list of frequency studies of Duchenne muscular dystrophy is included. The DMD mutation rate calculated by the indirect method is 7.9×10−5 genes per generation. However, this may well be an over-estimate, as this method does not account for germline mosaicism. Using a modified sex ratio method the proportion of sporadic DMD among all cases was estimated to be 0.106 (range 0–0.332). High frequency of germline mosaicism in DMD is a likely cause for the apparent lack of sporadic cases as found in previous studies, if mutation rates in male and female gametes are equal. Therefore, methods for estimating the proportion of new mutants in DMD should take germline mosaicism into account. The modified sex ratio method allows incorporation of data on germline mosaicism if available.