Central core disease is a
myopathy often arising from mutations in the type 1
ryanodine receptor (
RYR1) gene, encoding the sarcoplasmic reticulum
calcium release channel
RyR1. No treatment is currently available for this disease. We studied the pathological situation of a severely affected child with two recessive mutations, which resulted in a massive reduction in the amount of
RyR1. The paternal mutation induced the inclusion of a new in-frame pseudo-exon in
RyR1 mRNA that resulted in the insertion of additional
amino acids leading to the instability of the
protein. We hypothesized that skipping this additional exon would be sufficient to restore
RyR1 expression and to normalize
calcium releases. We therefore developed U7-AON lentiviral vectors to force exon skipping on affected primary muscle cells. The efficiency of the exon skipping was evaluated at the
mRNA level, at the
protein level, and at the functional level using
calcium imaging. In these affected cells, we observed a decreased inclusion of the pseudo-exon, an increased
RyR1 protein expression, and a restoration of
calcium releases of normal amplitude either upon direct
RyR1 stimulation or in response to membrane depolarization. This study is the first demonstration of the potential of exon-skipping strategy for the
therapy of
central core disease, from the molecular to the functional level.