Signs of Becker muscular dystrophy often include muscle problems, such as difficulty running, climbing stairs or getting up from the floor. Sometimes, Becker muscular dystrophy can be diagnosed after finding heart problems, with no other muscle symptoms. If a blood test is done, high levels of a protein called creatine kinase (CK) are seen. CK is normally found in muscle, but when muscles are damaged, such as in the case of Becker muscular dystrophy, it leaks into the bloodstream. The liver enzymes (aminotransferases, ALT and AST) are also often found to be high, but this is a consequence of the muscle damage and not of a liver problem.
Becker muscular dystrophy has to be confirmed by genetic testing, usually through a blood sample. Different types of genetic tests can provide specific and more detailed information about the genetic mutation. Genetic diagnosis is important as it offers a more accurate way of diagnosing Becker muscular dystrophy, and can therefore ensure adequate management. It can also help to identify other family members at risk of carrying the dystrophin mutation.
Your doctor may also recommend a muscle biopsy, where a small sample of muscle is taken for analysis (see our factsheet: Muscle biopsies). Tests on the muscle biopsy can provide information on the amount of dystrophin protein present in the muscle cells, and can help distinguish Becker muscular dystrophy from Duchenne muscular dystrophy and other muscular dystrophies. However, the clinical signs and the genetic test are usually sufficient to confirm the diagnosis, without the need to perform a muscle biopsy.