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Title
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A mosaic variant in CTNNB1/β-catenin as a novel cause for osteopathia striata with cranial sclerosis
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Author
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Abstract
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| Context: Osteopathia striata with cranial sclerosis (OSCS) is a rare bone disorder with X-linked dominant inheritance, characterized by a generalized hyperostosis in the skull and long bones and typical metaphyseal striations in the long bones. So far, loss-of-function variants in AMER1 (also known as WTX or FAM123B), encoding the APC membrane recruitment protein 1 (AMER1), have been described as the only molecular cause for OSCS. AMER1 promotes the degradation of beta-catenin via AXIN stabilization, acting as a negative regulator of the WNT/beta-catenin signaling pathway, a central pathway in bone formation.Objective: In this study, we describe a Dutch adult woman with an OSCS-like phenotype, namely, generalized high bone mass and characteristic metaphyseal striations, but no genetic variant affecting AMER1.Results: Whole exome sequencing led to the identification of a mosaic missense variant (c.876A > C; p.Lys292Asn) in CTNNB1, coding for beta-catenin. The variant disrupts an amino acid known to be crucial for interaction with AXIN, a key factor in the beta-catenin destruction complex. Western blotting experiments demonstrate that the p.Lys292Asn variant does not significantly affect the beta-catenin phosphorylation status, and hence stability in the cytoplasm. Additionally, luciferase reporter assays were performed to investigate the effect of p.Lys292Asn beta-catenin on canonical WNT signaling. These studies indicate an average 70-fold increase in canonical WNT signaling activity by p.Lys292Asn beta-catenin.Conclusion: In conclusion, this study indicates that somatic variants in the CTNNB1 gene could explain the pathogenesis of unsolved cases of osteopathia striata. |
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Language
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English
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Source (journal)
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The journal of clinical endocrinology and metabolism. - Baltimore, Md
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Publication
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Washington
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Endocrine soc
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2024
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ISSN
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0021-972X
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DOI
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10.1210/CLINEM/DGAD757
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Volume/pages
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109
:7
(2024)
, p. 1891-1898
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ISI
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001138679900001
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Pubmed ID
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38173341
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Full text (Publisher's DOI)
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Full text (open access)
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Full text (publisher's version - intranet only)
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