Muscle biopsy with dystrophic pattern and rimmed vacuoles: GNE myopathy in a Brazilian patient

Biópsia de músculo mostrando padrão distrófico e vacúolos marginados: um caso de miopatia GNE em uma paciente brasileira

GNE myopathy (MIM#605820) is a rare autosomal recessive disorder with a higher prevalence in individuals with Middle Eastern or Japanese ancestries¹. We present a 23-year-old Brazilian female, without such ancestries, with slowly progressive distal and proximal weakness in her lower limbs since the age of 18. Within five years, weakness progressed to her upper limbs and led to loss of ambulation (sparing the quadriceps somewhat). The muscle biopsy is shown in the Figure. Exome analysis revealed compound heterozygous variants on GNE gene (p.Arg193Cys, known², and p.Arg132Cys, novel). This is the first South American patient report, which illustrates the utility of high-throughput sequencing to diagnose rare and potentially treatable disorders^1,3.

Figure
Dystrophic pattern with rimmed vacuoles with autophagic aspect (arrows) on muscle biopsy. A) H&E (bar= 50 µm). B) Gomori's trichrome (bar= 50 µm). C) Acid phosphatase (bar= 50 µm). D) Electron microscopy (bar = 1000 nm).

References

• ¹
  Nishino I, Carrillo-Carrasco N, Argov Z. GNE myopathy: current update and future therapy. J Neurol Neurosurg Psychiatry. 2015;86(4):385-92. doi:10.1136/jnnp-2013-307051
  » https://doi.org/10.1136/jnnp-2013-307051
• ²
  Del Bo R, Baron P, Prelle A, Serafini M, Moggio M, Fonzo AD et al. Novel missense mutation and large deletion of GNE gene in autosomal-recessive inclusion-body myopathy. Muscle Nerve. 2003;28(1):113-7. doi:10.1002/mus.10391
  » https://doi.org/10.1002/mus.10391
• ³
  Mori-Yoshimura M, Nishino I. [Sialic acid replacement therapy for distal myopathy with rimmed vacuoles]. Brain Nerve. 2015;67(9):1115-23. Japanese. doi:10.11477/mf.1416200269
  » https://doi.org/10.11477/mf.1416200269

Publication Dates

• Publication in this collection
  Jan 2017

History

• Received
  22 July 2016
• Accepted
  01 Sept 2016