This is done in one of two ways: either a small piece of muscle is taken under general anaesthetic or a needle biopsy is performed to remove a small sample. The sample will be analysed under a microscope.
Muscle tissue from a person with minicore will have a characteristic pattern. Normal muscle tissue has two different types of fibre; type 1 and type 2.
Muscle from people with minicore myopathy has more type 1 fibres than type 2. Also, within these fibres, there are structures which are called ‘cores’; which can be seen under the microscope. These structures are not specific to minicore myopathy, and so the clinical signs must be considered together with the muscle sample to give a diagnosis of minicore myopathy.
A factsheet on Muscle biopsies is available from the Information and Support Line.
Molecular testing
Molecular testing is currently not available for minicore myopathy. It may be available for families where the specific genetic error has been identified, but a genetic testing centre would have to advise whether this was possible.
What other tests are available?
Since genetic testing is not available for this condition, prenatal diagnosis is also not available. In families where the error has been identified, both prenatal diagnosis and carrier testing may be possible, but a genetic testing centre would have to advise whether this was the case.