Your child may have seen a number of doctors before the diagnosis is made at a specialist centre.
It may be confirmed by taking blood tests, looking particularly at the level of the muscle enzyme creatine kinase (CK), by carrying out an EMG (electromyography) which detects abnormalities of electrical activity in muscle, by muscle ultrasound which shows an abnormal pattern of echoes in the muscle and by muscle biopsy which may demonstrate characteristic changes in the muscle under the microscope.
However, it must be stressed that none of these tests is entirely specific; even the muscle biopsy may be normal, as the changes in the muscles can be patchy. The diagnosis will be based on a combination of the clinical picture and results of some, but not necessarily all, of these tests.