The Prevalence of RYR1-related Disease

The skeletal muscle ryanodine receptor (RYR1) gene encodes an important calcium channel in skeletal muscle, with an important role in muscle contraction. Mutations (i.e. disease-causing changes) in RYR1 are associated with an immensely wide range of clinical problems, ranging from inborn muscle conditions with profound weakness at birth ("congenital myopathies"), to a potentially fatal anaesthesia complication ("Malignant Hyperthermia, MH") in otherwise healthy individuals. Although RYR1-related conditions are believed to be amongst the most common neuromuscular disorders, their precise prevalence (i.e. the number of cases in a particular population at a given time) is currently unknown. Moreover, there is no information regarding the relative frequency of specific congenital myopathies, MH and related manifestations, such as the associated bleeding abnormality recently described by our team.

The lack of reliable prevalence data represents a major obstacle to addressing the needs of individuals affected by RYR1-related conditions, to appropriate resource allocation, and to preparation for clinical studies ("trial-readiness") essential for therapy development.

To address this shortcoming, we will conduct an international collaborative study involving neuromuscular and MH centres from the UK and the Netherlands, focusing on the prevalence of RYR1-related conditions, as a group and per subtype. The countries participating in this study were included because of 1) centralized RYR1 testing, 2) the presence of at least one database/registry with population-wide coverage capturing RYR1-related disorders and 3) of national myopathy and MH expertise centres. Information regarding RYR1-mutated individuals and their specific diagnosis will be obtained from national databases/registries, and analysed utilizing statistical methods that are well-established in the field of epidemiology.

This study will provide important information regarding the actual disease burden of RYR1-related disorders on a wider scale, inform appropriate research resource allocation, and preparation for trial readiness. This study will be funded by the RYR1-Foundation.