Prospective Study of Adverse Event Rates in Males With X-Linked Myotubular Myopathy

X-Linked myotubular myopathy (XLMTM), a form of centronuclear myopathy (CNM) is the result of a mutation in the MTM1 (myotubularin) gene which leads to altered myotubularin. Myotubularin is essential for optimum muscle function. To date, over 100 mutations have been described resulting in a range of disease onset and symptom severity. The early onset form presents with neonatal hypotonia, muscle weakness, respiratory distress and an ongoing requirement for continuous ventilatory support with the inability to maintain a sitting position once placed. Males with both later onset and milder symptoms usually do not require ongoing ventilatory support, achieve a higher maximal motor function with ability to sit when placed and even walk, and have improved survival rates. Males with XLMTM may experience complications (events) at birth and throughout their lifetime. The goal of the study is to identify the number of events over twelve months in males with genetically confirmed XLMTM. Parents or affected individuals over the age of 18 years who are able to access telephone will provide answers to an established event survey to evaluate the frequency and types of events. Emergency department, hospital admissions and mortality will be confirmed by obtaining medical reports.

The investigators hypothesize that there will be no association between the frequency of events and markers of clinical severity including the need for ventilatory support at birth, current level of ventilatory support (no support, support less than 12 hours, support more than 12 hours) and current motor function (walking, sitting without support, inability to sit without support).