Getting a muscle biopsy can be a confusing and sometimes scary experience. To find out what happens in a day in the life of a muscle biopsy, follow the links below!

				Although sometimes a particular diagnosis is suspected on the basis of the symptoms and physical examination, it is important to see what is going on in the muscle itself.
				Muscle biopsies can be taken under local anaesthetic where a core of muscle is taken using a hollow needle, or under general anaesthetic, when a cut is made in the skin and a small piece of muscle is removed.
				No. The piece of muscle we take is small, and does not significantly affect the function of the muscle.
				There is usually some muscle left over and this is kept frozen and stored at -80 degrees C. New muscle proteins are being discovered all the time and we can continue to study these new proteins in the stored muscle biopsies.
				As the muscle disease process affects different muscles in different ways, we usually suggest taking a biopsy from two different sites. Muscular dystrophy usually affects the large 'limb-girdle' muscles so we take a biopsy from the deltoids in the upper arm, and the quadriceps in the front of the thigh.

		Examination of the basic structure and cells in the muscle. Normal muscle is made up of bundles of fibres which when cut in cross section look like this:the fibres are fairly uniform in size, and quite tightly packed.
		In muscular dystrophy, the muscle looks ‘dystrophic’. This means that there is degeneration and regeneration of muscle fibres going on in the muscle, the fibres are of varying sizes and some of the muscle has been replaced by connective or ‘scar’ tissue.

		Each muscle fibre is surrounded by a membrane, much like the banana skin surrounding the banana. There is a group of proteins that are found in the muscle membrane that help to link the muscle fibres together and stabilise the fibres when the muscle contracts. One of these proteins is called ‘dystrophin’, and the other proteins in the complex are called ‘dystrophin associated proteins’. In Duchenne muscular dystrophy (DMD), dystrophin is missing from the muscle, and the muscle is destabilised and becomes damaged with time. An abnormality in one of the other dystrophin associated proteins also results in muscle disease.

		We can study whether these proteins are present or absent by a process called immunohistochemistry. We use antibodies that recognise the proteins in the muscle membrane. These antibodies are labelled with a fluorescent dye so that we can see them. The figure shows the muscle cut in cross section. You can see in the normal muscle (1), the dystrophin lights up at the muscle membrane, outlining the muscle fibre. The next biopsy is from a boy with DMD (2), showing complete absence of dystrophin. The last biopsy (3) is from a man with Becker muscular dystrophy; the dystrophin is present but the staining is patchy and decreased in intensity.

		Although immunohistochemistry tells you whether the protein is present or not, we use another technique called ‘western blotting’ to more accurately tell us how much protein is there, and whether it is of normal size. You can see the band of normal dystrophin (1). There is no band at all in the boy with DMD (2), and in the man with BMD (3), there is less dystrophin and it is of a different size, and therefore does not function normally.

		The results of the immunohistochemistry and western blot on the muscle biopsy tell us that the dystrophin is abnormal. We now confirm this by looking for a mistake or "mutation" within the dystrophin gene itself.