| 1. |
- Angius, Andrea, et al.
(författare)
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Exome sequencing in Crisponi/cold-induced sweating syndrome-like individuals reveals unpredicted alternative diagnoses
- 2019
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Ingår i: Clinical Genetics. - : WILEY. - 0009-9163 .- 1399-0004. ; 95:5, s. 607-614
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Tidskriftsartikel (refereegranskat)abstract
- Crisponi/cold-induced sweating syndrome (CS/CISS) is a rare autosomal recessive disorder characterized by a complex phenotype (hyperthermia and feeding difficulties in the neonatal period, followed by scoliosis and paradoxical sweating induced by cold since early childhood) and a high neonatal lethality. CS/CISS is a genetically heterogeneous disorder caused by mutations in CRLF1 (CS/CISS1), CLCF1 (CS/CISS2) and KLHL7 (CS/CISS-like). Here, a whole exome sequencing approach in individuals with CS/CISS-like phenotype with unknown molecular defect revealed unpredicted alternative diagnoses. This approach identified putative pathogenic variations in NALCN, MAGEL2 and SCN2A. They were already found implicated in the pathogenesis of other syndromes, respectively the congenital contractures of the limbs and face, hypotonia, and developmental delay syndrome, the Schaaf-Yang syndrome, and the early infantile epileptic encephalopathy-11 syndrome. These results suggest a high neonatal phenotypic overlap among these disorders and will be very helpful for clinicians. Genetic analysis of these genes should be considered for those cases with a suspected CS/CISS during neonatal period who were tested as mutation negative in the known CS/CISS genes, because an expedited and corrected diagnosis can improve patient management and can provide a specific clinical follow-up.
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| 2. |
- Ekvall, S., et al.
(författare)
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Mutation in NRAS in familial Noonan syndrome - case report and review of the literature
- 2015
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Ingår i: Bmc Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Background: Noonan syndrome (NS), a heterogeneous developmental disorder associated with variable clinical expression including short stature, congenital heart defect, unusual pectus deformity and typical facial features, is caused by activating mutations in genes involved in the RAS-MAPK signaling pathway. Case presentation: Here, we present a clinical and molecular characterization of a small family with Noonan syndrome. Comprehensive mutation analysis of NF1, PTPN11, SOS1, CBL, BRAF, RAF1, SHOC2, MAP2K2, MAP2K1, SPRED1, NRAS, HRAS and KRAS was performed using targeted next-generation sequencing. The result revealed a recurrent mutation in NRAS, c.179G > A (p.G60E), in the index patient. This mutation was inherited from the index patient's father, who also showed signs of NS. Conclusions: We describe clinical features in this family and review the literature for genotype-phenotype correlations for NS patients with mutations in NRAS. Neither of affected individuals in this family presented with juvenile myelomonocytic leukemia (JMML), which together with previously published results suggest that the risk for NS individuals with a germline NRAS mutation developing JMML is not different from the proportion seen in other NS cases. Interestingly, 50 % of NS individuals with an NRAS mutation (including our family) present with lentigines and/or Cafe-au-lait spots. This demonstrates a predisposition to hyperpigmented lesions in NRAS-positive NS individuals. In addition, the affected father in our family presented with a hearing deficit since birth, which together with lentigines are two characteristics of NS with multiple lentigines (previously LEOPARD syndrome), supporting the difficulties in diagnosing individuals with RASopathies correctly. The clinical and genetic heterogeneity observed in RASopathies is a challenge for genetic testing. However, next-generation sequencing technology, which allows screening of a large number of genes simultaneously, will facilitate an early and accurate diagnosis of patients with RASopathies.
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| 3. |
- Frisk, Sofia, et al.
(författare)
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Early activating somatic PIK3CA mutations promote ectopic muscle development and upper limb overgrowth
- 2019
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Ingår i: Clinical Genetics. - : WILEY. - 0009-9163 .- 1399-0004. ; 96:2, s. 118-125
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Tidskriftsartikel (refereegranskat)abstract
- PIK3CA-related overgrowth spectrum is a group of rare genetic disorders with asymmetric overgrowth caused by somatic mosaic PIK3CA mutations. Here, we report clinical data and molecular findings from two patients with congenital muscular upper limb overgrowth and aberrant anatomy. During debulking surgery, numerous ectopic muscles were found in the upper limbs of the patients. DNA sequencing, followed by digital polymerase chain reaction, was performed on DNA extracted from biopsies from hypertrophic ectopic muscles and identified the somatic mosaic PIK3CA hotspot mutations c.3140A > G, p.(His1047Arg) and c.1624G > A, p.(Glu542Lys) in a male (patient 1) and a female (patient 2) patient, respectively. Patient 1 had four ectopic muscles and unilateral isolated muscular overgrowth while patient 2 had 13 ectopic muscles and bilateral isolated muscular overgrowth of both upper limbs, indicating that her mutation occurred at early pre-somitic mesoderm state. The finding of PIK3CA mutations in ectopic muscles highlights the importance of PIK3CA in cell fate in early human embryonic development. Moreover, our findings provide evidence that the disease phenotype depends on the timing of PIK3CA mutagenesis during embryogenesis and confirm the diagnostic entity PIK3CA-related muscular overgrowth with ectopic accessory muscles.
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| 4. |
- Gudmundsson, Sanna, et al.
(författare)
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A novel RAD21 p.(Gln592del) variant expands the clinical description of Cornelia de Lange syndrome type 4 : Review of the literature
- 2019
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Ingår i: European Journal of Medical Genetics. - : Elsevier. - 1769-7212 .- 1878-0849. ; 62:6
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Tidskriftsartikel (refereegranskat)abstract
- Cornelia de Lange syndrome (CdLS) is a heterogeneous developmental disorder where 70% of clinically diagnosed patients harbor a variant in one of five CdLS associated cohesin proteins. Around 500 variants have been identified to cause CdLS, however only eight different alterations have been identified in the RAD21 gene, encoding the RAD21 cohesin complex component protein that constitute the link between SMC1A and SMC3 within the cohesin ring. We report a 15-month-old boy presenting with developmental delay, distinct CdLS-like facial features, gastrointestinal reflux in early infancy, testis retention, prominent digit pads and diaphragmatic hernia. Exome sequencing revealed a novel RAD21 variant, c.1774_1776del, p.(Gln592del), suggestive of CdLS type 4. Segregation analysis of the two healthy parents confirmed the variant as de novo and bioinformatic analysis predicted the variant as disease-causing. Assessment by in silico structural model predicted that the p.Gln592del variant results in a discontinued contact between RAD21-Lys591 and the SMC1A residues Glu1191 and Glu1192, causing changes in the RAD21-SMC1A interface. In conclusion, we report a patient that expands the clinical description of CdLS type 4 and presents with a novel RAD21 p.(Glu592del) variant that causes a disturbed RAD21-SMC1A interface according to in silco structural modeling.
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| 5. |
- Gudmundsson, Sanna, 1989-, et al.
(författare)
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TAF1, associated with intellectual disability in humans, is essential for embryogenesis and regulates neurodevelopmental processes in zebrafish
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The TATA-box binding protein associated factor 1 (TAF1) protein is a key unit of the transcription factor II D complex that serves a vital function during transcription initiation. Variants of TAF1 have been associated with neurodevelopmental disorders, but TAF1's molecular functions remain elusive. In this study, we present a five-generation family affected with X-linked intellectual disability that co-segregated with a TAF1 c. 3568C>T, p.(Arg1190Cys) variant. All affected males presented with intellectual disability and dysmorphic features, while heterozygous females were asymptomatic and had completely skewed X-chromosome inactivation. We investigated the role of TAF1 and its association to neurodevelopment by creating the first complete knockout model of the TAF1 orthologue in zebrafish. A crucial function of human TAF1 during embryogenesis can be inferred from the model, demonstrating that intact taf1 is essential for embryonic development. Transcriptome analysis of taf1 zebrafish knockout revealed enrichment for genes associated with neurodevelopmental processes. In conclusion, we propose that functional TAF1 is essential for embryonic development and specifically neurodevelopmental processes.
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| 6. |
- Hu, H., et al.
(författare)
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X-exome sequencing of 405 unresolved families identifies seven novel intellectual disability genes
- 2016
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 21:1, s. 133-148
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Tidskriftsartikel (refereegranskat)abstract
- X-linked intellectual disability (XLID) is a clinically and genetically heterogeneous disorder. During the past two decades in excess of 100 X-chromosome ID genes have been identified. Yet, a large number of families mapping to the X-chromosome remained unresolved suggesting that more XLID genes or loci are yet to be identified. Here, we have investigated 405 unresolved families with XLID. We employed massively parallel sequencing of all X-chromosome exons in the index males. The majority of these males were previously tested negative for copy number variations and for mutations in a subset of known XLID genes by Sanger sequencing. In total, 745 X-chromosomal genes were screened. After stringent filtering, a total of 1297 non-recurrent exonic variants remained for prioritization. Co-segregation analysis of potential clinically relevant changes revealed that 80 families (20%) carried pathogenic variants in established XLID genes. In 19 families, we detected likely causative protein truncating and missense variants in 7 novel and validated XLID genes (CLCN4, CNKSR2, FRMPD4, KLHL15, LAS1L, RLIM and USP27X) and potentially deleterious variants in 2 novel candidate XLID genes (CDK16 and TAF1). We show that the CLCN4 and CNKSR2 variants impair protein functions as indicated by electrophysiological studies and altered differentiation of cultured primary neurons from Clcn4(-/-) mice or after mRNA knock-down. The newly identified and candidate XLID proteins belong to pathways and networks with established roles in cognitive function and intellectual disability in particular. We suggest that systematic sequencing of all X-chromosomal genes in a cohort of patients with genetic evidence for X-chromosome locus involvement may resolve up to 58% of Fragile X-negative cases.
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| 7. |
- Linhares, Natalia Duarte, et al.
(författare)
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1p13.2 deletion displays clinical features overlapping Noonan syndrome, likely related to NRAS gene haploinsufficiency
- 2016
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Ingår i: Genetics and Molecular Biology. - 1415-4757 .- 1678-4685. ; 39:3, s. 349-357
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Tidskriftsartikel (refereegranskat)abstract
- Deletion-induced hemizygosity may unmask deleterious autosomal recessive variants and be a cause of the phenotypic variability observed in microdeletion syndromes. We performed complete exome sequencing (WES) analysis to examine this possibility in a patient with 1p13.2 microdeletion. Since the patient displayed clinical features suggestive of Noonan Syndrome (NS), we also used WES to rule out the presence of pathogenic variants in any of the genes associated with the different types of NS. We concluded that the clinical findings could be attributed solely to the 1p13.2 haploinsufficiency. Retrospective analysis of other nine reported patients with 1p13.2 microdeletions showed that six of them also presented some characteristics of NS. In all these cases, the deleted segment included the NRAS gene. Gain-of-function mutations of NRAS gene are causally related to NS type 6. Thus, it is conceivable that NRAS haploinsufficiency and gain-of-function mutations may have similar clinical consequences. The same phenomenon has been described for two other genes belonging to the Ras/MAPK pathway: MAP2K2 and SHOC2. In conclusion, we here report genotype-phenotype correlations in patients with chromosome 1p13.2 microdeletions and we propose that NRAS may be a critical gene for the NS characteristics in the patients.
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| 8. |
- Schuster, Jens, et al.
(författare)
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Transcriptome Profiling Reveals Degree of Variability in Induced Pluripotent Stem Cell Lines : Impact for Human Disease Modeling
- 2015
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Ingår i: Cellular Reprogramming. - : Mary Ann Liebert Inc. - 2152-4971 .- 2152-4998. ; 17:5, s. 327-337
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Tidskriftsartikel (refereegranskat)abstract
- Induced pluripotent stem cell (iPSC) technology has become an important tool for disease modeling. Insufficient data on the variability among iPSC lines derived from a single somatic parental cell line have in practice led to generation and analysis of several, usually three, iPSC sister lines from each parental cell line. We established iPSC lines from a human fibroblast line (HDF-K1) and used transcriptome sequencing to investigate the variation among three sister lines (iPSC-K1A, B, and C). For comparison, we analyzed the transcriptome of an iPSC line (iPSC-K5B) derived from a different fibroblast line (HDF-K5), a human embryonic stem cell (ESC) line (ESC-HS181), as well as the two parental fibroblast lines. All iPSC lines fulfilled stringent criteria for pluripotency. In an unbiased cluster analysis, all stem cell lines (four iPSCs and one ESC) clustered together as opposed to the parental fibroblasts. The transcriptome profiles of the three iPSC sister lines were indistinguishable from each other, and functional pathway analysis did not reveal any significant hits. In contrast, the expression profiles of the ESC line and the iPSC-K5B line were distinct from that of the sister lines iPSC-K1A, B, and C. Differentiation to embryoid bodies and subsequent analysis of germ layer markers in the five stem cell clones confirmed that the distribution of their expression profiles was retained. Taken together, our observations stress the importance of using iPSCs of different parental origin rather than several sister iPSC lines to distinguish disease-associated mechanisms from genetic background effects in disease modeling.
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| 9. |
- Sobol, Maria, et al.
(författare)
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Transcriptome and Proteome Profiling of Neural Induced Pluripotent Stem Cells from Individuals with Down Syndrome Disclose Dynamic Dysregulations of Key Pathways and Cellular Functions
- 2019
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Ingår i: Molecular Neurobiology. - : Springer Science and Business Media LLC. - 0893-7648 .- 1559-1182. ; 56:10, s. 7113-7127
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Tidskriftsartikel (refereegranskat)abstract
- Down syndrome (DS) or trisomy 21 (T21) is a leading genetic cause of intellectual disability. To gain insights into dynamics of molecular perturbations during neurogenesis in DS, we established a model using induced pluripotent stem cells (iPSC) with transcriptome profiles comparable to that of normal fetal brain development. When applied on iPSCs with T21, transcriptome and proteome signatures at two stages of differentiation revealed strong temporal dynamics of dysregulated genes, proteins and pathways belonging to 11 major functional clusters. DNA replication, synaptic maturation and neuroactive clusters were disturbed at the early differentiation time point accompanied by a skewed transition from the neural progenitor cell stage and reduced cellular growth. With differentiation, growth factor and extracellular matrix, oxidative phosphorylation and glycolysis emerged as major perturbed clusters. Furthermore, we identified a marked dysregulation of a set of genes encoded by chromosome 21 including an early upregulation of the hub gene APP, supporting its role for disturbed neurogenesis, and the transcription factors OLIG1, OLIG2 and RUNX1, consistent with deficient myelination and neuronal differentiation. Taken together, our findings highlight novel sequential and differentiation-dependent dynamics of disturbed functions, pathways and elements in T21 neurogenesis, providing further insights into developmental abnormalities of the DS brain.
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| 10. |
- Terhal, Paulien A., et al.
(författare)
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A Study of the Clinical and Radiological Features in a Cohort of 93 Patients with a COL2A1 Mutation Causing Spondyloepiphyseal Dysplasia Congenita or a Related Phenotype
- 2015
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Ingår i: American Journal of Medical Genetics. Part A. - : Wiley. - 1552-4825 .- 1552-4833. ; 167A:3, s. 461-475
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Tidskriftsartikel (refereegranskat)abstract
- Type 2 collagen disorders encompass a diverse group of skeletal dysplasias that are commonly associated with orthopedic, ocular, and hearing problems. However, the frequency of many clinical features has never been determined. We retrospectively investigated the clinical, radiological, and genotypic data in a group of 93 patients with molecularly confirmed SEDC or a related disorder. The majority of the patients (80/93) had short stature, with radiological features of SEDC (n=64), others having SEMD (n=5), Kniest dysplasia (n=7), spondyloperipheral dysplasia (n=2), or Torrance-like dysplasia (n=2). The remaining 13 patients had normal stature with mild SED, Stickler-like syndrome or multiple epiphyseal dysplasia. Over 50% of the patients had undergone orthopedic surgery, usually for scoliosis, femoral osteotomy or hip replacement. Odontoid hypoplasia was present in 56% (95% CI 38-74) and a correlation between odontoid hypoplasia and short stature was observed. Atlanto-axial instability, was observed in 5 of the 18 patients (28%, 95% CI 10-54) in whom flexion-extension films of the cervical spine were available; however, it was rarely accompanied by myelopathy. Myopia was found in 45% (95% CI 35-56), and retinal detachment had occurred in 12% (95% CI 6-21; median age 14 years; youngest age 3.5 years). Thirty-two patients complained of hearing loss (37%, 95% CI 27-48) of whom 17 required hearing aids. The ophthalmological features and possibly also hearing loss are often relatively frequent and severe in patients with splicing mutations. Based on clinical findings, age at onset and genotype-phenotype correlations in this cohort, we propose guidelines for the management and follow-up in this group of disorders.
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