| 1. |
- Celse, Tristan, et al.
(författare)
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OTX2 duplications : a recurrent cause of oculo-auriculo-vertebral spectrum
- 2023
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Ingår i: Journal of Medical Genetics. - : BMJ Publishing Group Ltd. - 0022-2593 .- 1468-6244. ; 60:6, s. 620-626
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Tidskriftsartikel (refereegranskat)abstract
- Background Oculo-auriculo-vertebral spectrum (OAVS) is the second most common cause of head and neck malformations in children after orofacial clefts. OAVS is clinically heterogeneous and characterised by a broad range of clinical features including ear anomalies with or without hearing loss, hemifacial microsomia, orofacial clefts, ocular defects and vertebral abnormalities. Various genetic causes were associated with OAVS and copy number variations represent a recurrent cause of OAVS, but the responsible gene often remains elusive.Methods We described an international cohort of 17 patients, including 10 probands and 7 affected relatives, presenting with OAVS and carrying a 14q22.3 microduplication detected using chromosomal microarray analysis. For each patient, clinical data were collected using a detailed questionnaire addressed to the referring clinicians. We subsequently studied the effects of OTX2 overexpression in a zebrafish model.Results We defined a 272 kb minimal common region that only overlaps with the OTX2 gene. Head and face defects with a predominance of ear malformations were present in 100% of patients. The variability in expressivity was significant, ranging from simple chondromas to severe microtia, even between intrafamilial cases. Heterologous overexpression of OTX2 in zebrafish embryos showed significant effects on early development with alterations in craniofacial development.Conclusions Our results indicate that proper OTX2 dosage seems to be critical for the normal development of the first and second branchial arches. Overall, we demonstrated that OTX2 genomic duplications are a recurrent cause of OAVS marked by auricular malformations of variable severity.
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| 2. |
- Ramos, Jillian, et al.
(författare)
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Identification and rescue of a tRNA wobble inosine deficiency causing intellectual disability disorder
- 2020
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Ingår i: RNA. - : Cold Spring Harbor Laboratory. - 1355-8382 .- 1469-9001. ; 26:11, s. 1654-1666
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Tidskriftsartikel (refereegranskat)abstract
- The deamination of adenosine to inosine at the wobble position of tRNA is an essential post-transcriptional RNA modification required for wobble decoding in bacteria and eukaryotes. In humans, the wobble inosine modification is catalyzed by the heterodimeric ADAT2/3 complex. Here, we describe novel pathogenic ADAT3 variants impairing adenosine deaminase activity through a distinct mechanism that can be corrected through expression of the heterodimeric ADAT2 subunit. The variants were identified in a family in which all three siblings exhibit intellectual disability linked to biallelic variants in the ADAT3 locus. The biallelic ADAT3 variants result in a missense variant converting alanine to valine at a conserved residue or the introduction of a premature stop codon in the deaminase domain. Fibroblast cells derived fromtwo ID-affected individuals exhibit a reduction in tRNA wobble inosine levels and severely diminished adenosine tRNA deaminase activity. Notably, the ADAT3 variants exhibit impaired interaction with the ADAT2 subunit and alterations in ADAT2-dependent nuclear localization. Based upon these findings, we find that tRNA adenosine deaminase activity and wobble inosine modification can be rescued in patient cells by overexpression of the ADAT2 catalytic subunit. These results uncover a key role for the inactive ADAT3 deaminase domain in proper assembly with ADAT2 and demonstrate that ADAT2/3 nuclear import is required for maintaining proper levels of the wobble inosine modification in tRNA.
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| 3. |
- Sobol, Maria, et al.
(författare)
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Proximal Deletion 12q with a New Insight to Growth Retardation
- 2020
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Ingår i: Molecular Syndromology. - : S. Karger AG. - 1661-8769 .- 1661-8777. ; 11:3, s. 115-124
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Tidskriftsartikel (refereegranskat)abstract
- Proximal deletion of the long arm of chromosome 12 is a rare chromosomal abnormality described in about 20 patients. Known deletions span the region from 12q11 to 12q13 and include the genes YAF2, AMIGO2, and NELL2. These are suggested as candidate genes for the key phenotypic features such as growth and psychomotor retardation. Here, we present a case with a 3.1-Mb interstitial deletion at 12q12q13.11. The clinical observations of our patient overlap with the major common findings for published cases. The deletion detected in our patient does not involve the previously suggested candidate genes YAF2 and AMIGO2. We draw a correlation between proximal deletion 12q and ARID2 deficiency by comparing patients carrying gross deletions with a cohort of patients carrying small intragenic ARID2 deletions as well as patients with single nucleotide variants (SNVs) in ARID2. Growth retardation <-2 SD is present in cohorts with both gross and small deletions spanning ARID2. However, ARID2 SNVs do not correlate with severe growth retardation.
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| 4. |
- Thuresson, Ann-Charlotte, et al.
(författare)
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A novel heterozygous variant in FGF9 associated with previously unreported features of multiple synostosis syndrome 3
- 2021
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Ingår i: Clinical Genetics. - : John Wiley & Sons. - 0009-9163 .- 1399-0004. ; 99:2, s. 325-329
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Tidskriftsartikel (refereegranskat)abstract
- Human multiple synostoses syndrome 3 is an autosomal dominant disorder caused by pathogenic variants in FGF9. Only two variants have been described in FGF9 in humans so far, and one in mice. Here we report a novel missense variant c.566C>G, p.(Pro189Arg) in FGF9. Functional studies showed this variant impairs FGF9 homodimerization, but not FGFR3c binding. We also review the findings of cases reported previously and report on additional features not described previously.
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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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