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Advancing in Schaaf-Yang syndrome pathophysiology: from bedside to subcellular analyses of truncated MAGEL2

BACKGROUND: Schaaf-Yang syndrome (SYS) is caused by truncating mutations in MAGEL2, mapping to the Prader-Willi region (15q11-q13), with an observed phenotype partially overlapping that of Prader-Willi syndrome. MAGEL2 plays a role in retrograde transport and protein recycling regulation. Our aim is...

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Detalles Bibliográficos
Autores principales: Castilla-Vallmanya, Laura, Centeno-Pla, Mónica, Serrano, Mercedes, Franco-Valls, Héctor, Martínez-Cabrera, Raúl, Prat-Planas, Aina, Rojano, Elena, Ranea, Juan A G, Seoane, Pedro, Oliva, Clara, Paredes-Fuentes, Abraham J, Marfany, Gemma, Artuch, Rafael, Grinberg, Daniel, Rabionet, Raquel, Balcells, Susanna, Urreizti, Roser
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BMJ Publishing Group 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10086475/
https://www.ncbi.nlm.nih.gov/pubmed/36243518
http://dx.doi.org/10.1136/jmg-2022-108690
Descripción
Sumario:BACKGROUND: Schaaf-Yang syndrome (SYS) is caused by truncating mutations in MAGEL2, mapping to the Prader-Willi region (15q11-q13), with an observed phenotype partially overlapping that of Prader-Willi syndrome. MAGEL2 plays a role in retrograde transport and protein recycling regulation. Our aim is to contribute to the characterisation of SYS pathophysiology at clinical, genetic and molecular levels. METHODS: We performed an extensive phenotypic and mutational revision of previously reported patients with SYS. We analysed the secretion levels of amyloid-β 1–40 peptide (Aβ(1-40)) and performed targeted metabolomic and transcriptomic profiles in fibroblasts of patients with SYS (n=7) compared with controls (n=11). We also transfected cell lines with vectors encoding wild-type (WT) or mutated MAGEL2 to assess stability and subcellular localisation of the truncated protein. RESULTS: Functional studies show significantly decreased levels of secreted Aβ(1-40) and intracellular glutamine in SYS fibroblasts compared with WT. We also identified 132 differentially expressed genes, including non-coding RNAs (ncRNAs) such as HOTAIR, and many of them related to developmental processes and mitotic mechanisms. The truncated form of MAGEL2 displayed a stability similar to the WT but it was significantly switched to the nucleus, compared with a mainly cytoplasmic distribution of the WT MAGEL2. Based on the updated knowledge, we offer guidelines for the clinical management of patients with SYS. CONCLUSION: A truncated MAGEL2 protein is stable and localises mainly in the nucleus, where it might exert a pathogenic neomorphic effect. Aβ(1-40) secretion levels and HOTAIR mRNA levels might be promising biomarkers for SYS. Our findings may improve SYS understanding and clinical management.