STIR and diffusion-weighted MRI in asymptomatic hyperCKemia caused by ANO5-related myopathy

Sequências de difusão e STIR na ressonância magnética em hiperCKemia assintomática causada por miopatia associada ao ANO5

A 16-year-old man presented with four years of persistent hyperCKemia (20x the upper limit of the normal level) without any symptoms. The neurological examination was normal. No relevant family history or consanguinity were reported. A whole-body muscle MRI revealed normal T1 images, but it depicted hyperintensity in the medial gastrocnemius muscles by short tau inversion recovery (STIR) and diffusion-weighted imaging (DWI) sequences (Figure 1). Next-generation sequencing showed two variants, c.191dupA and c.2294A>G, in the ANO5 that encodes anoctamin-5, a chloride channel important for muscle membrane repair¹. Up to one-fourth of patients with recessive ANO5 mutations present with isolated hyperCKemia², and STIR/DWI hyperintensity can be the only relevant abnormality.

Figure 1.
MRI in asymptomatic hyperCKemia with ANO5 recessive variants.

References

• ¹
  Bolduc V, Marlow G, Boycott KM, Saleki K, Inoue H, Kroon J, et al. Recessive mutations in the putative calcium-activated chloride channel Anoctamin 5 cause proximal LGMD2L and distal MMD3 muscular dystrophies. Am J Hum Genet. 2010 Feb; 86(2): 213-21. https://doi.org/10.1016/j.ajhg.2009.12.013
  » https://doi.org/https://doi.org/10.1016/j.ajhg.2009.12.013
• ²
  Silva AMS, Coimbra-Neto AR, Souza PVS, Winckler PB, Gonçalves MVM, Cavalcanti EBU, et al. Clinical and molecular findings in a cohort of ANO5-related myopathy. Ann Clin Transl Neurol. 2019;6(7):1225-38. https://doi.org/10.1002/acn3.50801
  » https://doi.org/https://doi.org/10.1002/acn3.50801

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  Disclosures: Dr. Silva, Dr. Guimarães, Dr. Machado, and Dr. Zanoteli report no disclosures relevant to the manuscript.

Publication Dates

• Publication in this collection
  29 June 2020
• Date of issue
  Sept 2020

History

• Reviewed
  10 Feb 2020
• Received
  10 Feb 2020
• Accepted
  23 Mar 2020