People with inherited myopathies (which affect the structure of the muscles) can experience severe levels of disability and have a high risk of medical complications. Yet despite the significant impact on people's lives and high associated costs, we know little about who is affected and how. This makes providing effective services extremely challenging. This study aims to identify the frequency and impact of inherited myopathies in New Zealand. Adults and children diagnosed with an inherited myopathy will be identified through searching neurologists' and hospital records, community service databases, and through self-identification. Each person and a family/whanau member will be assessed to investigate the impact their condition has on their lives and the treatment they have received. Costs to the individual and society will be calculated. This study will identify critical areas where community and health care services could target resources to improve quality of life for those affected.