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- Beyerlein, Andreas, et al.
(författare)
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Progression from islet autoimmunity to clinical type 1 diabetes is influenced by genetic factors : Results from the prospective TEDDY study
- 2019
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 56:9, s. 602-605
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Tidskriftsartikel (refereegranskat)abstract
- Background: Progression time from islet autoimmunity to clinical type 1 diabetes is highly variable and the extent that genetic factors contribute is unknown. Methods: In 341 islet autoantibody-positive children with the human leucocyte antigen (HLA) DR3/DR4-DQ8 or the HLA DR4-DQ8/DR4-DQ8 genotype from the prospective TEDDY (The Environmental Determinants of Diabetes in the Young) study, we investigated whether a genetic risk score that had previously been shown to predict islet autoimmunity is also associated with disease progression. Results: Islet autoantibody-positive children with a genetic risk score in the lowest quartile had a slower progression from single to multiple autoantibodies (p=0.018), from single autoantibodies to diabetes (p=0.004), and by trend from multiple islet autoantibodies to diabetes (p=0.06). In a Cox proportional hazards analysis, faster progression was associated with an increased genetic risk score independently of HLA genotype (HR for progression from multiple autoantibodies to type 1 diabetes, 1.27, 95% CI 1.02 to 1.58 per unit increase), an earlier age of islet autoantibody development (HR, 0.68, 95% CI 0.58 to 0.81 per year increase in age) and female sex (HR, 1.94, 95% CI 1.28 to 2.93). Conclusions: Genetic risk scores may be used to identify islet autoantibody-positive children with high-risk HLA genotypes who have a slow rate of progression to subsequent stages of autoimmunity and type 1 diabetes.
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| 2. |
- Dhanraj, Santhosh, et al.
(författare)
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Bone marrow failure and developmental delay caused by mutations in poly(A)-specific ribonuclease (PARN)
- 2015
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 52:11, s. 738-748
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Tidskriftsartikel (refereegranskat)abstract
- Background Deadenylation regulates RNA function and fate. Poly(A)-specific ribonuclease (PARN) is a deadenylase that processes mRNAs and non-coding RNA. Little is known about the biological significance of germline mutations in PARN. Methods We identified mutations in PARN in patients with haematological and neurological manifestations. Genomic, biochemical and knockdown experiments in human marrow cells and in zebrafish have been performed to clarify the role of PARN in the human disease. Results We identified large monoallelic deletions in PARN in four patients with developmental delay or mental illness. One patient in particular had a severe neurological phenotype, central hypomyelination and bone marrow failure. This patient had an additional missense mutation on the non-deleted allele and severely reduced PARN protein and deadenylation activity. Cells from this patient had impaired oligoadenylation of specific H/ACA box small nucleolar RNAs. Importantly, PARN-deficient patient cells manifested short telomeres and an aberrant ribosome profile similar to those described in some variants of dyskeratosis congenita. Knocking down PARN in human marrow cells and zebrafish impaired haematopoiesis, providing further evidence for a causal link with the human disease. Conclusions Large monoallelic mutations of PARN can cause developmental/mental illness. Biallelic PARN mutations cause severe bone marrow failure and central hypomyelination.
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| 6. |
- Halvardson, Jonatan, et al.
(författare)
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Mutations in HECW2 are associated with intellectual disability and epilepsy
- 2016
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 53:10, s. 697-704
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: De novo mutations are a frequent cause of disorders related to brain development. We report the results of screening patients diagnosed with both epilepsy and intellectual disability (ID) using exome sequencing to identify known and new causative de novo mutations relevant to these conditions.METHODS: Exome sequencing was performed on 39 patient-parent trios to identify de novo mutations. Clinical significance of de novo mutations in genes was determined using the American College of Medical Genetics and Genomics standard guidelines for interpretation of coding variants. Variants in genes of unknown clinical significance were further analysed in the context of previous trio sequencing efforts in neurodevelopmental disorders.RESULTS: In 39 patient-parent trios we identified 29 de novo mutations in coding sequence. Analysis of de novo and inherited variants yielded a molecular diagnosis in 11 families (28.2%). In combination with previously published exome sequencing results in neurodevelopmental disorders, our analysis implicates HECW2 as a novel candidate gene in ID and epilepsy.CONCLUSIONS: Our results support the use of exome sequencing as a diagnostic approach for ID and epilepsy, and confirm previous results regarding the importance of de novo mutations in this patient group. The results also highlight the utility of network analysis and comparison to previous large-scale studies as strategies to prioritise candidate genes for further studies. This study adds knowledge to the increasingly growing list of causative and candidate genes in ID and epilepsy and highlights HECW2 as a new candidate gene for neurodevelopmental disorders.
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| 7. |
- Hofmeister, Wolfgang, et al.
(författare)
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CTNND2-a candidate gene for reading problems and mild intellectual disability.
- 2015
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 52:2, s. 111-22
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cytogenetically visible chromosomal translocations are highly informative as they can pinpoint strong effect genes even in complex genetic disorders.METHODS AND RESULTS: Here, we report a mother and daughter, both with borderline intelligence and learning problems within the dyslexia spectrum, and two apparently balanced reciprocal translocations: t(1;8)(p22;q24) and t(5;18)(p15;q11). By low coverage mate-pair whole-genome sequencing, we were able to pinpoint the genomic breakpoints to 2 kb intervals. By direct sequencing, we then located the chromosome 5p breakpoint to intron 9 of CTNND2. An additional case with a 163 kb microdeletion exclusively involving CTNND2 was identified with genome-wide array comparative genomic hybridisation. This microdeletion at 5p15.2 is also present in mosaic state in the patient's mother but absent from the healthy siblings. We then investigated the effect of CTNND2 polymorphisms on normal variability and identified a polymorphism (rs2561622) with significant effect on phonological ability and white matter volume in the left frontal lobe, close to cortical regions previously associated with phonological processing. Finally, given the potential role of CTNND2 in neuron motility, we used morpholino knockdown in zebrafish embryos to assess its effects on neuronal migration in vivo. Analysis of the zebrafish forebrain revealed a subpopulation of neurons misplaced between the diencephalon and telencephalon.CONCLUSIONS: Taken together, our human genetic and in vivo data suggest that defective migration of subpopulations of neuronal cells due to haploinsufficiency of CTNND2 contribute to the cognitive dysfunction in our patients.
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| 8. |
- Kalokairinou, Louiza, et al.
(författare)
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Regulating the advertising of genetic tests in Europe : a balancing act
- 2017
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 54:10, s. 651-656
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Tidskriftsartikel (refereegranskat)abstract
- Direct-to-consumer (DTC) genetic tests (GT) have provoked criticism over their potential adverse impact on public health. The European Parliament called for a ban on DTC advertising of GT during the debate for the adoption of a European Regulation on in vitro diagnostic medical devices. This proposal, however, was not ultimately retained in the final text. Instead, the regulation includes an article prohibiting misleading claims for this kind of advertising. These two different approaches raise questions about the optimal degree of regulation. Herein, we provide an overview of the ways GT have been advertised and related ethical issues. Subsequently, the laws regulating the advertising of GT at the European Union and national level are examined. Finally, recent regulatory developments are discussed.
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| 9. |
- Klar, Joakim, et al.
(författare)
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Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans
- 2015
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 52:9, s. 599-606
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Tidskriftsartikel (refereegranskat)abstract
- Background Keratosis pilaris atrophicans (KPA) is a group of rare genodermatoses characterised by perifollicular keratosis and inflammation that progresses to atrophy and scars of the facial skin. Keratosis pilaris of extensor areas of limbs is a common associated finding. Most cases with KPA are sporadic and no consistent inheritance pattern has been documented.Methods A large consanguineous Pakistani pedigree segregating autosomal recessive KPA of a mixed type was subject to autozygosity mapping and whole exome sequencing. Quantification of mRNA and protein levels was performed on fibroblasts from affected individuals. Cellular uptake of the low-density lipoprotein (LDL) receptor-related protein 1 (LRP1) ligand alpha 2-macroglobulin (alpha M-2) was quantified using fluorescence confocal microscopy.Results Genetic analyses identified a unique homozygous missense variant (K1245R) in the LRP1 in all affected family members. LRP1 encodes the LRP1, a multifunctional cell surface receptor with endocytic functions that belongs to the LDL receptor family. The LRP1 mRNA and LRP1 protein levels in fibroblasts of affected individuals were markedly reduced when compared with controls. Similarly, the LRP1-mediated cellular uptake of alpha M-2 was reduced in patient fibroblasts. Conclusions This is the first report on LRP1 as a pathogenic gene for autosomal recessive KPA and keratosis pilaris. The inflammatory characteristics of the KPA entity in our family suggest a link to the immune-regulatory functions of LRP1.
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| 10. |
- Kostjukovits, Svetlana, et al.
(författare)
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Decreased telomere length in children with cartilage-hair hypoplasia
- 2017
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Ingår i: Journal of Medical Genetics. - : BMJ PUBLISHING GROUP. - 0022-2593 .- 1468-6244. ; 54:5, s. 365-370
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Tidskriftsartikel (refereegranskat)abstract
- Background Cartilage-hair hypoplasia (CHH) is an autosomal recessive chondrodysplasia caused by RMRP (RNA component of mitochondrial RNA processing endoribonuclease) gene mutations. Manifestations include short stature, variable immunodeficiency, anaemia and increased risk of malignancies, all of which have been described also in telomere biology disorders. RMRP interacts with the telomerase RT (TERT) subunit, but the influence of RMRP mutations on telomere length is unknown. We measured relative telomere length (RTL) in patients with CHH, their first-degree relatives and healthy controls and correlated RTL with clinical and laboratory features. Methods The study cohort included 48 patients with CHH with homozygous (n=36) or compound heterozygous RMRP mutations (median age 38.2 years, range 6.0-70.8 years), 86 relatives (74 with a heterozygous RMRP mutation) and 94 unrelated healthy controls. We extracted DNA from peripheral blood, sequenced the RMRP gene and measured RTL by qPCR. Results Compared with age-matched and sex-matched healthy controls, median RTL was significantly shorter in patients with CHH (n=40 pairs, 1.05 vs 1.21, p=0.017), but not in mutation carriers (n=48 pairs, 1.16 vs 1.10, p=0.224). RTL correlated significantly with age in RMRP mutation carriers (r=-0.482, p < 0.001) and non-carriers (r=-0.498, p<0.001), but not in patients (r=-0.236, p=0.107). In particular children (< 18 years) with CHH had shorter telomeres than controls (median RTL 1.12 vs 1.26, p=0.008). In patients with CHH, RTL showed no correlation with genotype, clinical or laboratory characteristics. Conclusions Telomere length was decreased in children with CHH. We found no correlation between RTL and clinical or laboratory parameters.
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