W.C. Yee

Correction of dystrophia myotonica type 1 pre-mRNA transcripts by artificial trans -splicing

Dystrophia myotonica type 1 (DM1), the most common muscular dystrophy in adults, results from expansion of a CTG repeat in the 3′-untranslated region of the dystrophia myotonica protein kinase gene (DMPK). Correction of the mutant DMPK transcript is a potential therapeutic strategy in DM1. We investigated the efficacy of artificial trans-splicing molecules (ATMs) to target and correct DMPK transcripts. ATMs designed to target intron 14 of DMPK pre-mRNA transcripts were tested for their ability to trans-splice the transcripts of a DMPK mini-gene construct and the endogenous DMPK transcripts of human myosarcoma cells (CCL-136). On agarose gel electrophoresis analysis, six of eight ATMs showed trans-splicing efficacy when applied to DMPK mini-gene construct transcripts, of which three were able to trans-splice endogenous DMPK pre-mRNA transcripts in myosarcoma cells, with trans-splicing efficiency ranging from 1.81 to 7.41%. These findings confirm that artificial trans-splicing can repair DMPK pre-mRNA and provide proof-of-principle evidence for this approach as potential therapeutic strategy for DM1.

Characterization of a novel S13F desmin mutation associated with desmin myopathy and heart block in a Chinese family

Desmin myopathy was identified in a Chinese man with complete heart block and mild proximal and distal limb weakness. A novel heterozygous missense S13F mutation of the desmin gene was found to be associated with the myopathy. Family members carrying the mutation showed a similar or milder phenotype. The mutation is located at a protein kinase-C phosphorylation site within a highly conserved nonapeptide sequence in the head domain of the desmin protein. Expression of the mutant desmin cDNA in cell lines induced large desmin accumulations associated with preservation of a filamentous network.

Two eminently treatable genetic metabolic myopathies.

Treatment of the genetic metabolic myopathies remains generally unsatisfactory with the exception of a select few. Multiple Acyl Co-A Dehydrogenase Deficiency (Glutaric Aciduria type II), in particular, has been shown to respond well to riboflavin supplementation. Recently, studies have also confirmed the effectiveness of recombinant enzyme replacement therapy for Acid Maltase Deficiency (Pompes Disease). Accurate and early diagnosis of these diseases is vital to prevent serious complications and impaired recovery following delayed treatment.