Understanding the Impact of Non-Dystrophic Myotonia on Patients and Caregivers: Results from a Burden of Disease Healthcare Survey

Non-dystrophic myotonias (NDM) manifest as delayed muscle relaxation leading to muscle stiffness. This may diminish or worsen with repeated contractions, depending on NDM subtype. These are divided into those affecting the chloride channel CLC-1, due to CLCN1 gene mutations, and those affecting the sodium channel NaV1.4, due to SCN4A gene mutations. Depending on NDM subtype, additional symptoms and clinical signs of NDM can include transient weakness, myalgia, cramps, fatigue, dysphagia, dysphonia, and muscle hypertrophy. Two surveys, carried out independently but collectively named IMPACT (Impact of non-dystrophic Myotonia on PAtients and Caregivers’ qualiTy of life), were conducted to help elucidate how symptoms affect adults with NDM and those who care for adults or children with this condition. The patient survey not only confirmed NDM symptoms experienced by participants, but also highlighted how such symptoms affect a person’s quality of life, mental health, and abilities including problems with work, study, childcare, and socialising. Additionally, details of the diagnostic pathway, treatment, and healthcare professionals involved in NDM were revealed. The caregiver survey found that almost one-third of those who cared for someone with NDM did so for at least 10 hours per week. It also highlighted how a carer’s physical and mental health could be impacted by caregiving, potentially due to the finding that half of respondents felt that they had little or no support. Presented here are highlights of the IMPACT survey along with insights from five NDM clinical experts: Jordi Diaz-Manera, Channa Hewamadduma, Giovanni Meola, Federica Montagnese, and Sabrina Sacconi