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  • 1
    In: Nature Communications, Springer Science and Business Media LLC, Vol. 13, No. 1 ( 2022-01-10)
    Abstract: De novo mutations are known to play a prominent role in sporadic disorders with reduced fitness. We hypothesize that de novo mutations play an important role in severe male infertility and explain a portion of the genetic causes of this understudied disorder. To test this hypothesis, we utilize trio-based exome sequencing in a cohort of 185 infertile males and their unaffected parents. Following a systematic analysis, 29 of 145 rare (MAF  〈  0.1%) protein-altering de novo mutations are classified as possibly causative of the male infertility phenotype. We observed a significant enrichment of loss-of-function de novo mutations in loss-of-function-intolerant genes ( p -value = 1.00 × 10 −5 ) in infertile men compared to controls. Additionally, we detected a significant increase in predicted pathogenic de novo missense mutations affecting missense-intolerant genes ( p -value = 5.01 × 10 −4 ) in contrast to predicted benign de novo mutations. One gene we identify, RBM5 , is an essential regulator of male germ cell pre-mRNA splicing and has been previously implicated in male infertility in mice. In a follow-up study, 6 rare pathogenic missense mutations affecting this gene are observed in a cohort of 2,506 infertile patients, whilst we find no such mutations in a cohort of 5,784 fertile men ( p -value = 0.03). Our results provide evidence for the role of de novo mutations in severe male infertility and point to new candidate genes affecting fertility.
    Type of Medium: Online Resource
    ISSN: 2041-1723
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2553671-0
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  • 2
    In: Pharmaceutisch Weekblad, Springer Science and Business Media LLC, Vol. 11, No. S1 ( 1989-2), p. J3-J15
    Type of Medium: Online Resource
    ISSN: 0031-6911 , 1573-739X
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 1989
    detail.hit.zdb_id: 2008911-9
    detail.hit.zdb_id: 2601204-2
    SSG: 15,3
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  • 3
    In: Human Reproduction, Oxford University Press (OUP), Vol. 37, No. 6 ( 2022-05-30), p. 1360-1369
    Abstract: Are there more de novo mutations (DNMs) present in the genomes of children born through medical assisted reproduction (MAR) compared to spontaneously conceived children? SUMMARY ANSWER In this pilot study, no statistically significant difference was observed in the number of DNMs observed in the genomes of MAR children versus spontaneously conceived children. WHAT IS KNOWN ALREADY DNMs are known to play a major role in sporadic disorders with reduced fitness such as severe developmental disorders, including intellectual disability and epilepsy. Advanced paternal age is known to place offspring at increased disease risk, amongst others by increasing the number of DNMs in their genome. There are very few studies reporting on the effect of MAR on the number of DNMs in the offspring, especially when male infertility is known to be affecting the potential fathers. With delayed parenthood an ongoing epidemiological trend in the 21st century, there are more children born from fathers of advanced age and more children born through MAR every day. STUDY DESIGN, SIZE, DURATION This observational pilot study was conducted from January 2015 to March 2019 in the tertiary care centre at Radboud University Medical Center. We included a total of 53 children and their respective parents, forming 49 trios (mother, father and child) and two quartets (mother, father and two siblings). One group of children was born after spontaneous conception (n = 18); a second group of children born after IVF (n = 17) and a third group of children born after ICSI combined with testicular sperm extraction (ICSI-TESE) (n = 18). In this pilot study, we also subdivided each group by paternal age, resulting in a subgroup of children born to younger fathers ( & lt;35 years of age at conception) and older fathers ( & gt;45 years of age at conception). PARTICIPANTS/MATERIALS, SETTING, METHODS Whole-genome sequencing (WGS) was performed on all parent-offspring trios to identify DNMs. For 34 of 53 trios/quartets, WGS was performed twice to independently detect and validate the presence of DNMs. Quality of WGS-based DNM calling was independently assessed by targeted Sanger sequencing. MAIN RESULTS AND THE ROLE OF CHANCE No significant differences were observed in the number of DNMs per child for the different methods of conception, independent of parental age at conception (multi-factorial ANOVA, f(2) = 0.17, P-value = 0.85). As expected, a clear paternal age effect was observed after adjusting for method of conception and maternal age at conception (multiple regression model, t = 5.636, P-value = 8.97 × 10−7), with on average 71 DNMs in the genomes of children born to young fathers ( & lt;35 years of age) and an average of 94 DNMs in the genomes of children born to older fathers ( & gt;45 years of age). LIMITATIONS, REASONS FOR CAUTION This is a pilot study and other small-scale studies have recently reported contrasting results. Larger unbiased studies are required to confirm or falsify these results. WIDER IMPLICATIONS OF THE FINDINGS This pilot study did not show an effect for the method of conception on the number of DNMs per genome in offspring. Given the role that DNMs play in disease risk, this negative result is good news for IVF and ICSI-TESE born children, if replicated in a larger cohort. STUDY FUNDING/COMPETING INTEREST(S) This research was funded by the Netherlands Organisation for Scientific Research (918-15-667) and by an Investigator Award in Science from the Wellcome Trust (209451). The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER N/A.
    Type of Medium: Online Resource
    ISSN: 0268-1161 , 1460-2350
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 1484864-8
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  • 4
    In: Human Reproduction, Oxford University Press (OUP), Vol. 35, No. 1 ( 2020-01-01), p. 240-252
    Abstract: Can exome sequencing identify new genetic causes of globozoospermia? SUMMARY ANSWER Exome sequencing in 15 cases of unexplained globozoospermia revealed deleterious mutations in seven new genes, of which two have been validated as causing globozoospermia when knocked out in mouse models. WHAT IS KNOWN ALREADY Globozoospermia is a rare form of male infertility characterised by round-headed sperm and malformation of the acrosome. Although pathogenic variants in DPY19L2 and SPATA16 are known causes of globozoospermia and explain up to 70% of all cases, genetic causality remains unexplained in the remaining patients. STUDY DESIGN, SIZE, DURATION After pre-screening 16 men for mutations in known globozoospermia genes DPY19L2 and SPATA16, exome sequencing was performed in 15 males with globozoospermia or acrosomal hypoplasia of unknown aetiology. PARTICIPANTS/MATERIALS, SETTING, METHOD Targeted next-generation sequencing and Sanger sequencing was performed for all 16 patients to screen for single-nucleotide variants and copy number variations in DPY19L2 and SPATA16. After exclusion of one patient with DPY19L2 mutations, we performed exome sequencing for the 15 remaining subjects. We prioritised recessive and X-linked protein-altering variants with an allele frequency of & lt;0.5% in the population database GnomAD in genes with an enhanced expression in the testis. All identified candidate variants were confirmed in patients and, where possible, in family members using Sanger sequencing. Ultrastructural examination of semen from one of the patients allowed for a precise phenotypic characterisation of abnormal spermatozoa. MAIN RESULTS AND ROLE OF CHANCE After prioritisation and validation, we identified possibly causative variants in eight of 15 patients investigated by exome sequencing. The analysis revealed homozygous nonsense mutations in ZPBP and CCDC62 in two unrelated patients, as well as rare missense mutations in C2CD6 (also known as ALS2CR11), CCIN, C7orf61 and DHNA17 and a frameshift mutation in GGN in six other patients. All variants identified through exome sequencing, except for the variants in DNAH17, were located in a region of homozygosity. Familial segregation of the nonsense variant in ZPBP revealed two fertile brothers and the patient’s mother to be heterozygous carriers. Paternal DNA was unavailable. Immunohistochemistry confirmed that ZPBP localises to the acrosome in human spermatozoa. Ultrastructural analysis of spermatozoa in the patient with the C7orf61 mutation revealed a mixture of round heads with no acrosomes (globozoospermia) and ovoid or irregular heads with small acrosomes frequently detached from the sperm head (acrosomal hypoplasia). LIMITATIONS, REASONS FOR CAUTION Stringent filtering criteria were used in the exome data analysis which could result in possible pathogenic variants remaining undetected. Additionally, functional follow-up is needed for several candidate genes to confirm the impact of these mutations on normal spermatogenesis. WIDER IMPLICATIONS OF THE FINDINGS Our study revealed an important role for mutations in ZPBP and CCDC62 in human globozoospermia as well as five new candidate genes. These findings provide a more comprehensive understanding of the genetics of male infertility and bring us closer to a complete molecular diagnosis for globozoospermia patients which would help to predict the success of reproductive treatments. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by The Netherlands Organisation for Scientific Research (918–15-667); National Health and Medical Research Council of Australia (APP1120356) and the National Council for Scientific Research (CONICET), Argentina, PIP grant 11220120100279CO. The authors have nothing to disclose.
    Type of Medium: Online Resource
    ISSN: 0268-1161 , 1460-2350
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2020
    detail.hit.zdb_id: 1484864-8
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  • 5
    Online Resource
    Online Resource
    Georg Thieme Verlag KG ; 1985
    In:  Methods of Information in Medicine Vol. 24, No. 02 ( 1985-04), p. 57-64
    In: Methods of Information in Medicine, Georg Thieme Verlag KG, Vol. 24, No. 02 ( 1985-04), p. 57-64
    Abstract: Expert systems are an important extension of the research on medical decision making. Their relation to other research in this area is shortly discussed. Fourteen medical expert systems are examined from different perspectives. After a discussion of their goal, domain, and history, the classification of expert systems along the procedural-declarative continuum provides the basis for the analysis of their knowledge representations. As a result of this analysis, types of knowledge are identified that serve as a frame of reference for the comparison of the systems. Subsequently, the central role of these knowledge types in one of the most important tasks of expert systems, explaining, is emphasized. After the knowledge representation, two other components of expert systems are discussed that heavily depend on it: the knowledge acquisition and the man-machine interface. As a conclusion, the status quo of the research on expert systems is outlined and some developments are extrapolated. These developments show a tendency toward the integration of different knowledge types in one system.
    Type of Medium: Online Resource
    ISSN: 0026-1270 , 2511-705X
    RVK:
    Language: English
    Publisher: Georg Thieme Verlag KG
    Publication Date: 1985
    detail.hit.zdb_id: 3500-2
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  • 6
    Online Resource
    Online Resource
    Georg Thieme Verlag KG ; 1998
    In:  Methods of Information in Medicine Vol. 37, No. 04/05 ( 1998-10), p. 453-459
    In: Methods of Information in Medicine, Georg Thieme Verlag KG, Vol. 37, No. 04/05 ( 1998-10), p. 453-459
    Abstract: Update mechanisms for diagnostic classifications should capture changes in medical knowledge but also allow for comparability across versions. This paper provides a basis for such a mechanism by describing types of IS-A statement and types of knowledge used in the construction of diagnostic classifications. Three types of IS-A statement are used: ‘A is by definition a 8’, ‘A is probably a 8’ and ‘A is in theory necessarily a 8’. Each relates to a different type of knowedge: knowledge of linguistic conventions, of probabilities, and of empirical theories and their status, respectively. Consequently, the development and maintenance of diagnostic classifications requires a collaboration of medical terminologists and medical scientists. The role of the latter is especially important during updating. Updating is necessitated by changing probabilities and by the introduction or changing status of empirical theories. The linguistic notion of hyponymy oversimplifies the issue.
    Type of Medium: Online Resource
    ISSN: 0026-1270 , 2511-705X
    RVK:
    Language: English
    Publisher: Georg Thieme Verlag KG
    Publication Date: 1998
    detail.hit.zdb_id: 3500-2
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  • 7
    Online Resource
    Online Resource
    European Respiratory Society (ERS) ; 2008
    In:  European Respiratory Journal Vol. 31, No. 1 ( 2008-01-01), p. 84-92
    In: European Respiratory Journal, European Respiratory Society (ERS), Vol. 31, No. 1 ( 2008-01-01), p. 84-92
    Type of Medium: Online Resource
    ISSN: 0903-1936 , 1399-3003
    Language: English
    Publisher: European Respiratory Society (ERS)
    Publication Date: 2008
    detail.hit.zdb_id: 2834928-3
    detail.hit.zdb_id: 1499101-9
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  • 8
    Online Resource
    Online Resource
    Georg Thieme Verlag KG ; 2006
    In:  Methods of Information in Medicine Vol. 45, No. 03 ( 2006), p. 305-309
    In: Methods of Information in Medicine, Georg Thieme Verlag KG, Vol. 45, No. 03 ( 2006), p. 305-309
    Abstract: Objective: To determine whether educators consider electronic patient record (EPR)-related education necessary and if so, what subjects have to be taught more extensively in the future. Methods: A list of possibly relevant subjects was determined from the literature. A questionnaire was designed which contained those subjects and the respondents were asked to indicate, for each subject, its competency level and required competency level in current teaching. Since the response rate was low a second questionnaire was developed to have the results of the analysis of the first questionnaire validated by a larger group of educators. Results: In total 45 learning goals were identified from the literature. The questionnaire was sent to representatives of several disciplines: basic medical education, medical specializations, pharmacy, dentistry and nursing. The analysis of the first questionnaire resulted in nine subjects that needed more attention in the future. Because of the low response the needs could not be specified for the individual disciplines. This insight was obtained from a second questionnaire. The response to this questionnaire was high. From the analysis of the second questionnaire differences between views of educators involved in the training of GPs and educators involved in the training of other specializations were observed. Conclusion: Educators find EPR-related education important. There are different opinions about the phase in which EPR-related education should be given.
    Type of Medium: Online Resource
    ISSN: 0026-1270 , 2511-705X
    RVK:
    Language: English
    Publisher: Georg Thieme Verlag KG
    Publication Date: 2006
    detail.hit.zdb_id: 3500-2
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  • 9
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 1990
    In:  Pflügers Archiv Vol. 415, No. 4 ( 1990-1), p. 507-509
    In: Pflügers Archiv, Springer Science and Business Media LLC, Vol. 415, No. 4 ( 1990-1), p. 507-509
    Type of Medium: Online Resource
    ISSN: 0031-6768 , 1432-2013
    RVK:
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 1990
    detail.hit.zdb_id: 1463014-X
    SSG: 12
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  • 10
    Online Resource
    Online Resource
    Georg Thieme Verlag KG ; 2008
    In:  Methods of Information in Medicine Vol. 47, No. 02 ( 2008), p. 98-106
    In: Methods of Information in Medicine, Georg Thieme Verlag KG, Vol. 47, No. 02 ( 2008), p. 98-106
    Abstract: Objectives: In this study, we evaluated the internal validity of EPICON, an application for grouping ICPCcoded diagnoses from electronic medical records into episodes of care. These episodes are used to estimate morbidity rates in general practice. Methods: Morbidity rates based on EPICON were compared to a gold standard; i.e. the rates from the second Dutch National Survey of General Practice. We calculated the deviation from the gold standard for 677 prevalence and 681 incidence rates, based on the full dataset. Additionally, we examined the effect of casebased reasoning within EPICON using a comparison to a simple, not case-based method (EPI-0). Finally, we used a split sample procedure to evaluate the performance of EPICON. Results: Morbidity rates that are based on EPICON deviate only slightly from the gold standard and show no systematic bias. The effect of case-based reasoning within EPICON is evident. The addition of case-based reasoning to the grouping system reduced both systematic and random error. Although the morbidity rates that are based on the split sample procedure show no systematic bias, they do deviate more from the gold standard than morbidity rates for the full dataset. Conclusions: Results from this study indicate that the internal validity of EPICON is adequate. Assuming that the standard is gold, EPICON provides valid outcomes for this study population. EPICON seems useful for registries in general practice for the purpose of estimating morbidity rates.
    Type of Medium: Online Resource
    ISSN: 0026-1270 , 2511-705X
    RVK:
    Language: English
    Publisher: Georg Thieme Verlag KG
    Publication Date: 2008
    detail.hit.zdb_id: 3500-2
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