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. Perform a CK Test
   2. Elevated CK^* (>250U/L)
   3. Promptly refer to a neuromuscular specialist or geneticist ^{Footnotes Footnotes Footnotes Footnotes Footnotes 1,3,5}
   4. Test for DMD gene deleteion or duplication using MLPA or CGH
   5. Mutation found: DMD Diagnosis
      ~70–80% of DMD patients
   6. No mutation found: Perform sanger or NGS to test for small scale mutations in the DMD GENE
   7. Mutation found: DMD Diagnosis
      ~20–30% of DMD patients
   8. No mutation found: Perform muscle biopsy
   9. 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
   10. Dystrophin present: DMD unlikely; Consider alternative diagnoses