The first step in diagnosing FSHD is a visit with a doctor for a physical exam. An initial diagnosis is based on the pattern of muscles affected. The doctor will ask a series of questions about the patient’s family history and medical history (see Symptoms).
The doctor may order tests to determine whether the problems are a result of FSHD. Tests may also rule out other problems that could cause muscle weakness, such as surgery, toxic exposure, medications, or other diseases. These tests may include the following:
- Blood tests to measure levels of serum creatine kinase (CK), an enzyme that is released into the bloodstream when muscle fibers are deteriorating, and serum aldolase, an enzyme that helps break down sugars into energy. Elevated levels of either of these enzymes can indicate a problem with muscles and a need for additional testing. However, a normal CK level does not rule out FSHD.
- Neurological tests to rule out other nervous system disorders, identify patterns of muscle weakness and wasting, test reflexes and coordination, and detect muscle contractures.
- Muscle biopsies, which involve the removal of muscle tissue using a biopsy needle or during a simple surgical procedure. The tissue is then examined under a microscope. In FSHD, a muscle biopsy might reveal several abnormalities, but none are uniquely characteristic for the disease, or the muscle might even appear normal. To confirm a diagnosis of FSHD with certainty, a genetic test is needed.
- Genetic testing to confirm FSHD Type 1 or Type 2.
Adapted from NIH Health Topics.