PRO136 Symptoms and Impacts of Nonsense Mutation Duchenne Muscular Dystrophy at Different Stages of Ambulation

Abstract

Duchenne muscular dystrophy (DMD) is a rare genetic neuromuscular disorder which causes progressive muscle degeneration and weakness, and leads to loss of motor function and premature death. The aim of this study was to understand the symptoms and impacts of nonsense mutation DMD (nmDMD) at different stages of ambulation. Semi-structured qualitative telephone interviews were conducted with caregivers of individuals with nmDMD treated with ataluren in the UK. The interviews explored the symptoms and impacts of nmDMD, as well as impacts on caregivers. Participants also completed a background questionnaire with questions which enabled categorisation into three different health states (HS) according to level of ambulation. Qualitative data were analysed using thematic analysis and symptoms/impacts were compared across HS. Ten interviews were conducted with parents of individuals aged 4-19 years. Six participants had children who were in an early ambulatory HS (can rise from supine, stand and walk 10 metres), three in a late ambulatory HS (can stand and walk 10 metres) and one in an intermediate HS (can stand). In line with the HS definitions, increasing HS severity was related to a decreasing physical function and independent action, such as the ability to walk, run/jump, climb stairs and get up off the floor, and increasing fatigue. This impacted the individuals’ ability to take part in daily and social activities, and their emotional wellbeing. This declining physical function was reflected in an increased level of care and emotional burden reported by caregivers. As individuals with nmDMD lose ambulation, their decline in physical function can lead to impairments in other areas of life, which can impact their health-related quality of life (HRQoL) and that of their caregivers. Treatments which delay progression have the potential to prevent loss of function and decline in HRQoL of individuals and their caregivers.