A real-world analysis of an XLMTM patient cohort from the MTM and CNM international patient registry

*Correspondence: [e-mail].

Abstract

Background: X-linked myotubular myopathy (XLMTM) is a rare genetic neuromuscular disorder for which there is limited real-world data.

Objective: To describe demographic and clinical characteristics of male patients with XLMTM in the Myotubular Myopathy (MTM) and Centronuclear Myopathy (CNM) Patient Registry.

Methods: We performed a cross-sectional analysis of a genetically confirmed, living male patient cohort with XLMTM from the international MTM and CNM Patient Registry. As the data are patient-entered, some analyses had different denominators due to varying response rates for certain questions. Results were de-identified and reported at the aggregate level from patients’ most recent data entry. Analyses were not performed for response rates ≤2 patients. Data lock was on July 22nd, 2022.

Results: A total of N=88 patients were included. Mean age was 11.7 years (range: 0 to 59 years). Mean age at genetic report was 4.1 years (range: 0 to 46 years) for n=73 responding patients. Fifty-four of 85 responding patients (63.5%) had received a muscle biopsy. The best motor milestone reported by patients (n=79) was 43.2% unable to sit or walk without support, 7.4% able to walk supported, 16.1% able to sit on their own, 21.0% able walk on their own, and 12.4% unknown. Of 88 patients, most (73.9%) reported requiring ventilation at birth; approximately 45.5% reported currently utilizing ventilation ≥16 hours/day, 25.0% utilized <16 hours/day, including while sleeping and awake, 9.1% utilized ventilation <16 hours/day, but only while sleeping, and 10.2% did not utilize ventilation. Of 82 responses, 58.5% reported feeding tube only, 30.5% reported no feeding tube, and 11% reported a gastric or nasal tube with some oral feeding. Of 81 responses, 55.6%, 4.9%, and 29.6% reported using a wheelchair all the time, some of the time, and never, respectively.

Conclusion: The MTM-CNM Patient Registry provides a unique opportunity to examine real-world data in patients with XLMTM with evidence of varying severity. Data suggests that the disease burden of XLMTM is substantial, with most patients experiencing limited motor function and requiring respiratory support at birth and in daily life. Use of assistive devices and gastric or nasal tubes was common. Limitations include varying response rates, missing data, and the cross-sectional nature of this analysis. These data contribute to the understanding of XLMTM and highlight the need for improved treatments for these patients.

Publication History

Article published online:
12 May 2025