Medicines for Duchenne muscular dystrophy

What it is

Duchenne muscular dystrophy (DMD) is a genetic condition that causes progressive muscle weakness and wasting. It is caused by a change in the gene for a muscle protein called dystrophin, which is important for keeping muscle cells healthy; without working dystrophin, the muscles gradually become damaged and weaken over time. Because the gene is on the X chromosome, DMD almost always affects boys (girls are usually carriers, and only rarely affected). Symptoms usually begin in early childhood — often noticed as delayed walking, frequent falls, difficulty running, climbing stairs or getting up from the floor (sometimes using the hands to "walk up" the legs, a characteristic sign), and enlarged calf muscles. The muscle weakness is progressive, affecting mobility over the years, and over time can also affect the muscles involved in breathing and the heart, which are important aspects of care. Learning and developmental differences occur in some. DMD is a serious, life-limiting condition, but — importantly — care has improved greatly, and a coordinated, proactive approach now significantly improves quality of life and life expectancy compared with the past, with ongoing advances including new treatments for some people. It is diagnosed with blood tests and genetic testing.

How it is treated

DMD is managed by a specialist multidisciplinary team, with a coordinated, proactive approach that has substantially improved outcomes. Care is tailored to the stage of the condition and aims to maintain function, prevent and manage complications, and support quality of life. Key elements include: physiotherapy and support to maintain movement and prevent joint tightness, and equipment and aids to support mobility as needed; steroids (corticosteroids), which are an important treatment that can slow the progression of muscle weakness and are widely used; and, crucially, proactive monitoring and management of the heart and breathing, as these are affected over time — with heart medicines and breathing support introduced as needed, which has been a major factor in improving life expectancy. Managing bones (as steroids and reduced mobility affect bone health), nutrition, and other aspects, plus educational and psychological support and support for the whole family, are all part of comprehensive care. Newer treatments, including some targeted genetic therapies, are available or in development for certain genetic subtypes, and specialist teams advise on these. Genetic counselling is offered to families. The reassuring message is that, although DMD is a serious, progressive condition, modern coordinated care — including steroids and proactive heart and breathing management — significantly improves quality of life and survival, and the field is advancing, so specialist care and support are central.