Diagnosis of DMD Footnote 1

  1. Positive family history with suspicion of abnormal muscle function Footnote 1
    1. Perform a CK Test
    2. Normal CK
    3. Patients with missed motor milestones should be referred to a neuromuscular specialist Footnote 3
  2. Developmental delay, such as difficulty rising to stand or not walking well be 18 months Footnotes Footnotes Footnotes Footnotes 1–4
    1. Perform a CK Test
  3. Unexplained increases in transaminases Footnote 1
    1. Elevated CK* (>250U/L)
    2. Promptly refer to a neuromuscular specialist or geneticist Footnotes Footnotes Footnotes Footnotes Footnotes 1,3,5
    3. Test for DMD gene deleteion or duplication using MLPA or CGH
    4. Mutation found: DMD Diagnosis
      ~70–80% of DMD patients
    5. No mutation found: Perform sanger or NGS to test for small scale mutations in the DMD GENE
    6. Mutation found: DMD Diagnosis
      ~20–30% of DMD patients
    7. No mutation found: Perform muscle biopsy
    8. Dystrophin absent: DMD diagnosis; test for deep intronic mutations in DMD GENE with MRNA analysis
      ~0.3% of DMD patients have a deep intronic mutation
    9. Dystrophin present: DMD unlikely; Consider alternative diagnoses