| 1. |
- Akram, Talia, et al.
(författare)
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Aberrant splicing due to a novel RPS7 variant causes Diamond-Blackfan Anemia associated with spontaneous remission and meningocele
- 2020
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Ingår i: International Journal of Hematology. - : Springer Science and Business Media LLC. - 0925-5710 .- 1865-3774. ; 112:6, s. 894-899
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Tidskriftsartikel (refereegranskat)abstract
- Diamond-Blackfan Anemia (DBA) is a congenital pure red cell aplasia caused by heterozygous variants in ribosomal protein genes. The hematological features associated with DBA are highly variable and non-hematological abnormalities are common. We report herein on an affected mother and her daughter presenting with transfusion-dependent anemia. The mother showed mild physical abnormalities and entered spontaneous remission at age 13 years. Her daughter was born with occipital meningocele. Exome sequencing of DNA from the mother revealed a heterozygous novel splice site variant (NM_001011.4:c.508-3T > G) in the Ribosomal Protein S7 gene (RPS7) inherited by the daughter. Functional analysis of the RPS7 variant expressed from a mini-gene construct revealed that the exon 7 acceptor splice site was replaced by a cryptic splice resulting in a transcript missing 64 bp of exon 7 (p.Val170Serfs*8). Our study confirms a pathogenic effect of a novel RPS7 variant in DBA associated with spontaneous remission in the mother and meningocele in her daughter, thus adding to the genotype-phenotype correlations in DBA.
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| 2. |
- Fatima, Ambrin, et al.
(författare)
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Generation of a human Neurochondrin deficient iPSC line KICRi002-A-3 using CRISPR/Cas9
- 2020
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Ingår i: Stem Cell Research. - : Elsevier BV. - 1873-5061 .- 1876-7753. ; 44
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The role of Neurochondrin (NCDN) in humans is not well understood. Mice with a conditional Ncdn knock-out show epileptic seizures, depressive-like behaviours and impaired spatial learning. Using CRISPR/Cas9, we generated a Neurochondrin deficient human iPSC line KICRi002-A-3 carrying a homozygous 752 bp deletion / 2 bp insertion in the NCDN gene. The iPSC line maintained a normal 46,XY karyotype, expressed pluripotency markers and exhibited capability to differentiate into the three germ layers in vitro. Off-target editing was excluded and Neurochondrin expression was not detectable. The iPSC line offers a valuable resource to study the role of Neurochondrin during human neurogenesis.
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| 3. |
- Fatima, Ambrin, et al.
(författare)
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Incontinentia pigmenti : Generation of an IKBKG deficient human iPSC line (KICRi002-A-1) on a 46,XY background using CRISPR/Cas9
- 2020
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Ingår i: Stem Cell Research. - : Elsevier BV. - 1873-5061 .- 1876-7753. ; 44
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Incontinentia pigmenti (IP) is an X-linked dominant neuroectodermal dysplasia caused by loss-of-function mutations in the IKBKG gene. Using CRISPR/Cas9 technology, we generated an IKBKG knock-out iPSC line (KICRi002-A-1) on a 46,XY background. The iPSC line showed a normal karyotype, expressed pluripotency markers and exhibited capability to differentiate into the three germ layers in vitro. Off-target editing was excluded and no IKBKG mRNA expression could be detected. Our line offers a useful resource to elucidate mechanisms caused by IKBKG deficiency that leads to disrupted male fetal development and for drug screening to improve treatment of female patients with IP.
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| 4. |
- Fatima, Ambrin, et al.
(författare)
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Monoallelic and bi-allelic variants in NCDN cause neurodevelopmental delay, intellectual disability, and epilepsy
- 2021
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Ingår i: American Journal of Human Genetics. - : Cell Press. - 0002-9297 .- 1537-6605. ; 108:4, s. 739-748
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Tidskriftsartikel (refereegranskat)abstract
- Neurochondrin (NCDN) is a cytoplasmatic neural protein of importance for neural growth, glutamate receptor (mGluR) signaling, and synaptic plasticity. Conditional loss of Ncdn in mice neural tissue causes depressive-like behaviors, impaired spatial learning, and epileptic seizures. We report on NCDN missense variants in six affected individuals with variable degrees of developmental delay, intellectual disability (ID), and seizures. Three siblings were found homozygous for a NCDN missense variant, whereas another three unrelated individuals carried different de novo missense variants in NCDN. We assayed the missense variants for their capability to rescue impaired neurite formation in human neuroblastoma (SH-SY5Y) cells depleted of NCDN. Overexpression of wild-type NCDN rescued the neurite-phenotype in contrast to expression of NCDN containing the variants of affected individuals. Two missense variants, associated with severe neurodevelopmental features and epilepsy, were unable to restore mGluR5-induced ERK phosphorylation. Electrophysiological analysis of SH-SY5Y cells depleted of NCDN exhibited altered membrane potential and impaired action potentials at repolarization, suggesting NCDN to be required for normal biophysical properties. Using available transcriptome data from human fetal cortex, we show that NCDN is highly expressed in maturing excitatory neurons. In combination, our data provide evidence that bi-allelic and de novo variants in NCDN cause a clinically variable form of neurodevelopmental delay and epilepsy, highlighting a critical role for NCDN in human brain development.
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| 5. |
- Thuresson, Ann-Charlotte, et al.
(författare)
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Novel PNKP mutations associated with reduced DNA single-strand break repair and severe microcephaly, seizures, and developmental delay
- 2024
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Ingår i: Molecular Genetics & Genomic Medicine. - : John Wiley & Sons. - 2324-9269. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Microcephaly with early-onset seizures (MCSZ) is a neurodevelopmental disorder caused by pathogenic variants in the DNA strand break repair protein, polynucleotide kinase 3 '-phosphatase (PNKP).Methods: We have used whole genome sequencing and Sanger sequencing to identify disease-causing variants, followed by a minigene assay, Western blotting, alkaline comet assay, gamma H2AX, and ADP-ribose immunofluorescence.Results: Here, we describe a patient with compound heterozygous variants in PNKP, including a missense variant in the DNA phosphatase domain (T323M) and a novel splice acceptor site variant within the DNA kinase domain that we show leads to exon skipping. We show that primary fibroblasts derived from the patient exhibit greatly reduced levels of PNKP protein and reduced rates of DNA single-strand break repair, confirming that the mutated PNKP alleles are dysfunctional.Conclusion: The data presented show that the detected compound heterozygous variants result in reduced levels of PNKP protein, which affect the repair of both oxidative and TOP1-induced single-strand breaks, and most likely causes MCSZ in this patient.
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| 6. |
- Zakaria, Muhammad, et al.
(författare)
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Primary microcephaly, primordial dwarfism, and brachydactyly in adult cases with biallelic skipping of RTTN exon 42
- 2019
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 40:7, s. 899-903
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Tidskriftsartikel (refereegranskat)abstract
- Biallelic and pathogenic variants in the RTTN gene, encoding the centrosomal protein Rotatin, are associated with variable degrees of neurodevelopmental abnormalities, microcephaly, and extracranial malformations. To date, no reported case has reached their third decade. Herein, we report on a consanguineous family with three adult members, age 43, 57, and 60 years respectively, with primary microcephaly, developmental delay, primordial dwarfism, and brachydactyly segregating a homozygous splice site variant NM_173630.3:c.5648–5T>A in RTTN. The variant RTTN allele results in a nonhypomorphic skipping of exon 42 and a frameshift [(NP_775901.3:p.Ala1883Glyfs*6)]. Brain MRI of one affected individual showed markedly reduced volume of cerebral lobes and enlarged sulci but without signs of neural migration defects. Our assessment of three adult cases with a biallelic RTTN variant shows that a predicted shortened Rotatin, lacking the C‐terminal end, are associated with stationary clinical features into the seventh decade. Furthermore, our report adds brachydactyly to the phenotypic spectrum in this pleiotropic entity.
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