An early sign of Duchenne or Becker is that the person is struggling with standing and walking. DMD or BMD people will often have trouble with climbing stairs and have an unsteady way of walking. In some cases, the calves are enlarged, because the muscle tissue gets replaced by fat and scar tissue. In Duchenne, the majority of the children are later in reaching motor milestones, such as walking, hopping and crawling. In a minority of the children, the first symptom is delayed speech. When walking becomes more difficult, children tend to walk on their toes.
Becker symptoms are often initially seen as ‘clumsiness’ in falling often due to muscle weakness in the hips, pelvis and legs. The loss of muscle tissue is not painful in itself, although some patients mention having muscle cramps.
Confirming the diagnosis
Genetic testing will confirm the diagnosis of Duchenne and Becker and show the exact mutation in the gene. Often the first test is a blood test measuring CK (creatine kinase), which is extremely elevated in DMD and BMD. However, this is a general biomarker for muscle break down. So the next step is to see if DMD/BMD or another disease is causing the muscle breakdown. This is done by looking at the dystrophin gene in the blood. In the majority of cases, the deletion will be found. In rare cases, when it is impossible to confirm the diagnosis through this test, a biopsy is performed to confirm the diagnosis by the absence (or quasi-absence) of dystrophin.