The RYR1 gene is unusual in size (106 exons) and thus is too complex to be fully screened for mutations.
The strategy of RYR1 testing based on DHPLC and targeted sequencing appears to be a cost-effective option.
We must take into account that 14 families (of 52) were previously tested by single-strand conformation polymorphism analysis with negative results and that one RYR1 mutation was detected by DHPLC alone.
50] values for the different RYR1 activators, which were highly statistically significant (caffeine [EC.
2+] concentration in myotubes derived from patients in the accelerated group were more pronounced at lower concentrations of all three RYR1 activators tested compared to the non-accelerated group (Figure 2).
Several studies have confirmed that muscles from patients susceptible to MH are more sensitive to direct RYR1 activators such as caffeine, halothane and 4-CmC (22-25), but the criteria of [EC.
Central core disease is due to RYR1
mutations in more than 90% of patients.
Samples of genomic DNA from 38 individuals with known positive IVCTs (MHS or MHE) were sequenced over RYR1 exons 1 to 20, 38 to 47, 85 to 87, 98 to 104 covering the known hotspots.
The six microsatellite markers flanking the RYR1 locus were used to determine the haplotypes of each of the families displaying identical mutations.
Sequencing of 'hot-spot' areas proved to be an effective, if somewhat limited, way of examining for RYR1 mutations.
It has previously been reported that the RYR1 mutation in patient 2 (L4838V) was responsible for MH incidents, based on its expression in Chinese hamster ovary cells in functional assay (14).
In conclusion, we observed propofol-induced changes in myoplasmic calcium concentrations in cultured human skeletal muscle cells obtained from carriers of the RYR1 R2508C and L4838V mutations.