[MIM 310 400]

Prevalence: 1-9/1.106. Form of X-linked severe centro-nuclear myopathy (see this term). Mutation of the MTM1 gene (Xq27.3-q28) coding for myotubularin. It is sometimes associated with an anomaly in the development of the external genitalia (contiguous genes phenomenon [MIM 300 219]. The women carrying the mutation can present with a phenotype of variable gravity.

At histological examination, the nuclei of the muscle cells are gathered at the centre of the cell and not in the sarcolemma. Moreover muscle fibres keep an immature tube-shaped appearance ('myotube'). There is no cardiac muscle involvement.

Major neonatal hypotonia with facial diplegia, respiratory failure and swallowing problems. Often rapidly lethal.

Often: macrosomia, with a size greater than the 90th percentile and increased cranial circumference: narrow, elongated face; external ophthalmoplegia.  Pyloric stenosis and hepatic cavernous hemangiomas have been reported in some cases of prolonged survival.

For cases surviving until adolescence: scoliosis, temporomandibular joint ankylosis, tracheotomy and nighttime ventilation intermittently then permanently.

Anesthetic implications:

management of a patient at risk of malignant hyperthermia; monitoring of curarization (reduced muscle mass) and of decurarization

References : 

• Quinn RD, Pae WE, McGary S, Wickey GS. 
  Development of malignant hyperthermia during mitral valve replacement. 
  Ann Thor Surg 1992; 53: 1114-6.
• Breslin D, Reid J, Hayes A, Mirakhur RK. 
  Anaesthesia and myotubular (centronuclear) myopathy. 
  Anaesthesia 2000 ; 55 : 471-4.
• Costi D, Van Der Walt J. 
  General anesthesia in an infant with X-linked myotubular myopathy. 
  Pediatr Anesth 2004 ; 14 : 964-8.
• Schmid E, Jöhr M, Berger T. 
  X-linked myotubular myopathy: anesthetic management for muscle biopsy.
  Pediatr Anesth 2006 ; 16 : 218-9.
• Christiaens F, Van den Bergh PYK. 
  Les myopathies congénitales. 
  Louvain Med 2014 ; 133 : 478-90.
• North K, Wang C, Clarke N, Jungbluth H, Vainzof M, Dowling J et al. 
  Approach to the diagnosis of congenital myopathies. 
  Neuromuscul Disord 2014 ; 24 : 97-116.
• Flaherty DC, Lonner B, Gal JS.
  Successful management of a patient with X-linked myotubular myopathy for scoliosis surgery and previous cardiac arrest after prone positioning: a case report.
  A&A Practice 2018; 10: 340-2.

Updated: July 2021