Non-coding VMA21 deletions cause X-linked Myopathy with Excessive Autophagy

A. Ruggieri, N. Ramachandran, P. Wang, E. Haan, C. Kneebone, J. Manavis, L. Morandi, I. Moroni, P. Blumbergs, M. Mora, B. A. Minassian

Research output: Contribution to journalArticle

Abstract

X-linked Myopathy with Excessive Autophagy (XMEA) affects proximal muscles of the lower extremities and follows a progressive course reminiscent of muscular dystrophy. It is caused by mutations in VMA21 whose protein product assembles lysosomes' proton pumps. All XMEA mutations to date have been single-nucleotide substitutions that reduce VMA21 expression, which leads to modest lysosomal pH increase, the first step in the disease's pathogenesis. We now report a new class of XMEA mutations. We identified two VMA21 non-coding microdeletions, one intronic (c.54-16_54-8del), the other in the 3'UTR (c.*13_*104del). Both resulted in a relatively more severe (early ambulation loss), diffuse (extra-ocular and upper extremity involvement), and early (neonatal) onset disease compared to previously reported patients. Our cases highlight the importance of including non-coding regions of VMA21 in genetic testing panels of dystrophies and myopathies. Specific diagnosis of XMEA will be particularly important as therapies aimed at correcting the modest rise in lysosomal pH at the root of this disease are developed.

Original languageEnglish
Pages (from-to)207-211
Number of pages5
JournalNeuromuscular Disorders
Volume25
Issue number3
DOIs
Publication statusPublished - Mar 1 2015

Keywords

  • Autophagy
  • Lysosomal atPase
  • Microdeletions
  • VMA21
  • XMEA

ASJC Scopus subject areas

  • Clinical Neurology
  • Pediatrics, Perinatology, and Child Health
  • Genetics(clinical)
  • Neurology
  • Medicine(all)

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    Ruggieri, A., Ramachandran, N., Wang, P., Haan, E., Kneebone, C., Manavis, J., Morandi, L., Moroni, I., Blumbergs, P., Mora, M., & Minassian, B. A. (2015). Non-coding VMA21 deletions cause X-linked Myopathy with Excessive Autophagy. Neuromuscular Disorders, 25(3), 207-211. https://doi.org/10.1016/j.nmd.2014.11.014