Antisense Morpholino-Based In Vitro Correction of a Pseudoexon-Generating Variant in the SGCB Gene.
Francesca MagriSimona ZanottiSabrina SalaniFrancesco FortunatoPatrizia CiscatoSimonetta GereviniLorenzo MaggiMonica SciaccoMaurizio MoggioStefania CortiNereo BresolinGiacomo Pietro ComiDario RonchiPublished in: International journal of molecular sciences (2022)
Limb-girdle muscular dystrophies (LGMD) are clinically and genetically heterogenous presentations displaying predominantly proximal muscle weakness due to the loss of skeletal muscle fibers. Beta-sarcoglycanopathy (LGMDR4) results from biallelic molecular defects in SGCB and features pediatric onset with limb-girdle involvement, often complicated by respiratory and heart dysfunction. Here we describe a patient who presented at the age of 12 years reporting high creatine kinase levels and onset of cramps after strenuous exercise. Instrumental investigations, including a muscle biopsy, pointed towards a diagnosis of beta-sarcoglycanopathy. NGS panel sequencing identified two variants in the SGCB gene, one of which (c.243+1548T>C) was found to promote the inclusion of a pseudoexon between exons 2 and 3 in the SGCB transcript. Interestingly, we detected the same genotype in a previously reported LGMDR4 patient, deceased more than twenty years ago, who had escaped molecular diagnosis so far. After the delivery of morpholino oligomers targeting the pseudoexon in patient-specific induced pluripotent stem cells, we observed the correction of the physiological splicing and partial restoration of protein levels. Our findings prompt the analysis of the c.243+1548T>C variant in suspected LGMDR4 patients, especially those harbouring monoallelic SGCB variants, and provide a further example of the efficacy of antisense technology for the correction of molecular defects resulting in splicing abnormalities.
Keyphrases
- skeletal muscle
- copy number
- end stage renal disease
- induced pluripotent stem cells
- case report
- muscular dystrophy
- chronic kidney disease
- genome wide
- ejection fraction
- newly diagnosed
- heart failure
- insulin resistance
- peritoneal dialysis
- resistance training
- single molecule
- single cell
- atrial fibrillation
- high intensity
- gene expression
- metabolic syndrome
- ultrasound guided
- rna seq
- type diabetes
- intellectual disability
- genome wide identification
- drug delivery
- tyrosine kinase
- amino acid
- patient reported
- young adults
- protein protein