Duchenne muscular dystrophy (DMD) is primarily diagnosed through a combination of blood tests and genetic testing, looking for signs of muscle damage and specific gene mutations.
Here's a breakdown of the typical diagnostic process:
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Creatine Kinase (CK) Blood Test:
- The doctor will take a blood sample to measure the level of creatine kinase (CK).
- CK is an enzyme released by damaged muscles.
- Significantly elevated CK levels are often the first indication of DMD. A high CK level suggests muscle damage, warranting further investigation.
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Genetic Testing:
- This is the most definitive diagnostic test.
- Doctors analyze a blood sample to identify mutations in the DMD gene, which provides instructions for making dystrophin. Dystrophin is a protein essential for muscle structure and function.
- Genetic testing can confirm the DMD diagnosis by identifying the specific mutation.
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Muscle Biopsy (less common):
- Although less frequently used now due to the accuracy of genetic testing, a muscle biopsy may be performed in some cases, particularly if genetic testing results are inconclusive or to assess the amount of dystrophin present.
- A small sample of muscle tissue is removed and examined under a microscope.
- The biopsy can show the absence or deficiency of dystrophin, a hallmark of DMD.
In summary, the diagnosis of Duchenne muscular dystrophy typically involves a blood test to check CK levels, followed by genetic testing to confirm the diagnosis by identifying a mutation in the DMD gene. Muscle biopsies are less commonly used but may be considered in certain situations.
