1,721,335 research outputs found
Clinical and molecular basis of transient neonatal diabetes mellitus in Brazilian children
No full textWe report a series of patients with transient neonatal diabetes mellitus (TNDM). Paternal uniparental isodisomy of chromosome 6 and heterozygous KCNJ11 and ABC88 mutation were the mutations found. This first reported series of Brazilian patients expands the geographical data on TNDM contributing to better understanding of its pathophysiology
Semi-automated unidirectional sequence analysis for mutation detection in a clinical diagnostic setting
No full textBACKGROUND: The past 10 years have seen an improvement in sequence data quality due to the introduction of capillary sequencers and new sequencing chemistries. In parallel, new software programs for automated mutation detection have been developed. We evaluated the sensitivity of semiautomated unidirectional sequence analysis for the detection of heterozygous base substitutions using the Mutation Surveyor software package.METHODS: Detection rates for heterozygous base substitutions in 29 genes by automated and visual inspection were compared. Examples of heterozygous bases not detected in one direction during bidirectional analysis were also sought through a national survey of United Kingdom (UK) genetics laboratories. Sequence quality was assessed in a consecutive cohort of 50 patients for whom the 39 exons of the ABCC8 gene had been sequenced in one direction.RESULTS: A total of 701 different heterozygous base substitutions were detected by the software with no false negatives (sensitivity >or=99.57%). Four examples of heterozygous bases missed in one direction during bidirectional analysis were reported. Two were detected using unidirectional analysis settings, and the other two bases had low-quality scores. Of the 1950 amplicons examined, 97.2% had a quality score >or=30 and an average PHRED-like score >or=50 for the defined region of interest, and 98.1% of the 323,650 bases had a PHRED score >40.CONCLUSIONS: We found no evidence to support a requirement for bidirectional sequencing. Semiautomated analysis of good quality unidirectional sequence data has high sensitivity and is suitable for heterozygote mutation scanning in clinical diagnostic laboratories. Further work is required to determine minimum quality parameters for semiautomated analysis.<br/
Clinical and genetic features of Argentinian children with diabetes-onset before 12 months of age: successful transfer from insulin to oral sulfonylurea
No full textAims Neonatal diabetes mellitus (NDM) is a rare monogenic disorder, reported to affect less than 2 cases per 100,000 infants. There are two types, permanent (PNDM) and transient (TNDM). We describe our clinical experience in determining and comparing the genetic basis of diabetes in children with onset before 6 months versus those diagnosed between 6 and 12 months of age.Methods We reviewed medical records of children with diabetes diagnosed before 12 months of age. Genetic testing was performed in all cases.Results 12 patients were diagnosed with diabetes before 6 months of age (PNDM = 6; TNDM = 6), and 11 patients between 6 and 12 months (all with permanent diabetes). Among children with PNDM, we identified three different KCNJ11 mutations in 5 patients, and one novel ABCC8 mutation in a single patient. Among children with TNDM, we detected a KCNJ11 and ABCC8 mutation each in a single patient and methylation abnormalities at chromosome 6q24 in 4 patients.Among children with diabetes diagnosed between 6 and 12 months, 1 patient had an INS mutation and one patient was homozygous for an SLC19A2 mutation which confirmed a diagnosis of thiamine-responsive megaloblastic anaemia syndrome. Five of the patients with an ABCC8 or KCNJ11 mutation have successfully transferred from insulin to glibenclamide whist 1 child demonstrated a partial response to sulfonylurea treatment.Conclusions Investigating the underlying genetic basis of diabetes in children with onset before 1 year is useful for choosing the most efficient treatment, the basis of Personalized Medicine
Rare disease genomic testing in the UK and Ireland:Promoting timely and equitable access
Full text linkPurpose and scope The aim of this position statement is to provide recommendations regarding the delivery of genomic testing to patients with rare disease in the UK and Ireland. The statement has been developed to facilitate timely and equitable access to genomic testing with reporting of results within commissioned turnaround times. Methods of statement development A 1-day workshop was convened by the UK Association for Clinical Genomic Science and attended by key stakeholders within the NHS Genomic Medicine Service, including clinical scientists, clinical geneticists and patient support group representatives. The aim was to identify best practice and innovations for streamlined, geographically consistent services delivering timely results. Attendees and senior responsible officers for genomic testing services in the UK nations and Ireland were invited to contribute. Results and conclusions We identified eight fundamental requirements and describe these together with key enablers in the form of specific recommendations. These relate to laboratory practice (proportionate variant analysis, bioinformatics pipelines, multidisciplinary team working model and test request monitoring), compliance with national guidance (variant classification, incidental findings, reporting and reanalysis), service development and improvement (multimodal testing and innovation through research, informed by patient experience), service demand, capacity management, workforce (recruitment, retention and development), and education and training for service users. This position statement was developed to provide best practice guidance for the specialist genomics workforce within the UK and Ireland but is relevant to any publicly funded healthcare system seeking to deliver timely rare disease genomic testing in the context of high demand and limited resources.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Genomic variant sharing: a position statement
Full text linkSharing de-identified genetic variant data is essential for the practice of genomic medicine and is demonstrably beneficial to patients. Robust genetic diagnoses that inform medical management cannot be made accurately without reference to genetic test results from other patients, as well as population controls. Errors in this process can result in delayed, missed or erroneous diagnoses, leading to inappropriate or missed medical interventions for the patient and their family. The benefits of sharing individual genetic variants, and the harms of not sharing them, are numerous and well-established. Databases and mechanisms already exist to facilitate deposition and sharing of pseudonomised genetic variants, but clarity and transparency around best practice is needed to encourage widespread use, prevent inconsistencies between different communities, maximise individual privacy and ensure public trust. We therefore recommend that widespread sharing of a small number of individual genetic variants associated with limited clinical information should become standard practice in genomic medicine. Information robustly linking genetic variants with specific conditions is fundamental biological knowledge, not personal information, and therefore should not require consent to share. For additional case-level detail about individual patients or more extensive genomic information, which is often essential for clinical interpretation, it may be more appropriate to use a controlled-access model for data sharing, with the ultimate aim of making as much information as open and de-identified as possible with appropriate consent.</ns4:p
New insights into autoimmune mediated neonatal diabetes
No full textMonogenic autoimmune diseases are highly variable syndromes that usually have onset in the first year of life and are often fatal in early childhood. Identifying monogenic autoimmune diabetes is important as it can have implications for medical management of patients, informs families and clinicians of prognosis and recurrence risk, and gives insights into beta-cell autoimmunity and immune tolerance.
The first section of this thesis introduces monogenic autoimmune disease, with focus on the conditions that have autoimmune endocrine disorders as part of their clinical phenotype. The following section details the methodologies used throughout this thesis.
In chapter 1, we used a type 1 diabetes genetic risk score (T1D-GRS) based on the top 10 risk alleles for T1D to identify patients with monogenic autoimmunity from patients with early-onset polygenic diabetes and additional autoimmunity. We showed that the T1D-GRS was highly discriminatory of monogenic autoimmunity, especially when combined with age of onset (ROC-AUC 0.88). We also identified 16 families for gene discovery studies. Furthermore, this work shows that polygenic risk for the development of T1D does not affect the development of diabetes in monogenic autoimmunity.
Chapter 2 describes the genetic and phenotypic information for the largest cohort of patients with IPEX syndrome, caused by hemizygous mutations in FOXP3, reported to date (n=48). We analysed this data to determine if there were any genotypic or clinical characteristics of IPEX syndrome that could predict prognosis. We did not find evidence of phenotype-genotype relationships and showed that presenting feature did not predict prognosis. Medical management of IPEX syndrome cannot, therefore, be based on genotype or presentation.
In chapter 3 we employed whole exome sequencing to look for causal variant(s) in a patient with diabetes (diagnosed aged 7 weeks) and autoimmune lymphoproliferative disease. This identified recessively inherited causative variants in LRBA. We then used targeted next generation sequencing (NGS) to screen a large cohort of patients (n=169) and identified an additional 8 probands and an affected family member. This confirms the role of LRBA as a neonatal diabetes gene, bringing the total number of genes to 25.
In chapter 4, we assessed if immunoglobulin E (IgE) could be useful to identify patients with early-onset multisystem autoimmune disease caused by gain of function (GOF) STAT3 mutations. We showed that serum IgE was below the lower limit of the normal reference range (2KU/L) in all patients with STAT3 GOF (n=6), giving this threshold a sensitivity of 100% (95% CI: 54.1 – 100) and specificity 97.2% (95% CI: 96.2-97.9). We also found that IgE in patients with IPEX (n=16) was significantly higher than those with STAT3 GOF (p=0.002) suggesting it could be useful to identify IPEX from STAT3 GOF in non-consanguineous males with early-onset autoimmunity.
The final concluding section summarises the key findings of each chapter, the impact of these findings and suggests future avenues for research.
Identifying monogenic autoimmunity has enabled prenatal diagnoses, given families and clinicians knowledge on recurrence risk, and could enable targeted therapies to be employed. This body of work will enable better discrimination of monogenic autoimmunity from polygenic clustering of early-onset autoimmunity, and gives insights into the factors that determine disease phenotype and clinical course in monogenic autoimmunity. Gene discovery on the remaining patients will give new insights into the mechanisms of beta-cell autoimmunity and the regulation of the adaptive immune system and maintenance of immune tolerance.Wellcome Trus
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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