Diagnosis of MH Susceptibility

The preferred first line of investigation for a patient presenting to the neurology clinic with features associated with MH susceptibility is DNA analysis.  If a variant in the RYR1 gene is found, it will fall into one of the following categories:

• Known benign variant, eg common polymorphism
• Pathogenic for myopathy and MH susceptibility
• Pathogenic for myopathy but not pathogenic for MH susceptibility
• Pathogenic for myopathy but significance for MH susceptibility unknown
• Variant of unknown significance