Table 9 Rationale for myopathy investigation

1. Complete anamnesis and neurological physical examination;

2. Family history with pedigree;

3. Exclude four common neuromuscular diagnosis that may be diagnosed clinically and confirmed by molecular studies:

 - Spinal muscular atrophy (SMA)

 - Myotonic dystrophy type 1 (DM1, Steinert’s myotonic dystrophy)

 - Facioscapulohumeral muscular dystrophy (FSHD)

 - Dystrophinopathy type Duchenne muscular dystrophy

4. Electromyogram;

5. Muscle serum enzymes: creatine kinase, aldolase;

6. Muscle imaging: magnetic resonance imaging (MRI), ultrasound, ocasionally computed tomography for patients that cannot be submitted to MRI (e.g., pacemaker users, metal implants, etc.);

7. Brain imaging if suspected of encephalomyopathy.

8. According to the clinical suspicion: Muscle biopsy or Molecular Studies such as Next Generation Sequencing (NGS) or targeted molecular sequencing of the specific gene group related to muscle biopsy findings.