Your window into Astellas’ world of patient-centered and science-driven healthcare, as told by the experts who bring it to life.
This article features real families sharing their personal experiences and is available to the public for informational purposes only. Individual experiences may vary. It does not offer personalized medical advice or patient-specific treatment guidance. Please consult your healthcare provider for medical advice.
From the moment they take their first breath, many children born with X-linked myotubular myopathy (XLMTM) face a fight for strength and survival. Often, they spend the first several months of their lives in and out of the hospital,1 supported by machines that help them breathe and teams of specialists who monitor every heartbeat.
Children living with XLMTM are extremely vulnerable, facing a heightened risk of respiratory infections and requiring constant, round-the-clock care. And yet, there are currently no approved drug or therapeutic treatments designed specifically for XLMTM. Today, care focuses on symptom management and optimizing quality of life as best as possible.
Lucy James
Asset Lead
XLMTM is a rare disease that occurs when there are changes in the MTM1 gene, which causes the absence or dysfunction of a protein called myotubularin, a peptide critical in the development, maturation and maintenance of muscle cells.2 “It’s a loss of function — anything you’re using muscles for, you have a hard time with,” says Lucy James, Asset Lead at Astellas. “Sitting, crawling, crying, talking, feeding, all of these things are severely compromised.”
The condition predominantly impacts boys because the affected gene is on the X-chromosome and unlike girls, who have two X chromosomes, boys only have one. It is estimated that 1 in every 50,000 males is affected,3 and of the males born with XLMTM, half don’t survive beyond 18 months of age. While females can carry an affected XLMTM gene and are less likely to be severely affected, there is a growing understanding and appreciation that females can also experience a range of symptoms and may be severely affected, depending on how the gene expresses itself.4,5
Chelsea Moran
Patient Partnerships
Lead, Established and
International Markets
But the future for this rare disease can be different. By working together with the XLMTM community, researchers and caregivers, there’s a growing hope of better understanding and caring for children affected by the disease and their families.
“We recognize the urgent need to advance research and treatment for XLMTM,” says Chelsea Moran, Patient Partnerships Lead, Established & International Markets at Astellas. “It is critical that we listen to and collaborate with the community so we can create value for the XLMTM community as defined by them.”
The uncertainty surrounding XLMTM often begins long before a diagnosis is made. For many parents, the signs appear early — a baby who struggles to move, breathe or feed — but answers can be slow to come.
Because XLMTM is so rare, it’s often not identified prior to birth unless there is a previously known family history. It is not currently part of standard pre-natal testing panels. Even for mothers who experience reduced fetal movement and polyhydramnios during pregnancy, the condition is rarely detected prior to delivery.
After birth, the search for answers can be just as difficult. Neuromuscular diseases can look alike in the earliest stages and genetic testing isn’t always immediately available.6,7,8 The diagnostic process can sometimes stretch on for months, leaving parents in the dark about their baby’s condition.
Sometimes, however, the right specialist can change everything. There are experts who can spot the subtle signs of XLMTM and differentiate it from other neuromuscular disorders, and consulting with one at the right moment may make all the difference in a child’s care and survival.
That’s what happened to Anne Lennox, whose son Tom was diagnosed thanks to a friend who helped her connect with a specialist in London. “The lead doctor took a long look at Tom and said, ‘He’s one of ours,’” Anne recalls. “Although it wasn’t good news, it was done in a way that welcomed Tom and viewed him as a real person, not just an unanswered diagnosis.”
Finding the right care is another immense challenge for families living with XLMTM. There are only a handful of established centers that offer specialized care for the condition, leaving many parents to seek care far from their homes. Some families spend months traveling back and forth between the hospital and home, while others choose to relocate temporarily, uprooting their lives to be closer to care.
Erin Ward, whose son Will was born in 2001 with XLMTM, says that her family was fortunate to live near Boston Children’s Hospital, which helped her build a strong, supportive care team for him. But for many families, especially those who live in rural areas far from major medical centers, that kind of access simply is not possible.
Without a health system that is set up to effectively support children with XLMTM, parents often become the primary coordinators of care. Adding to that difficulty is the expectation that surrounds parents to communicate with multiple specialists about how best to care for their child, Erin says. “It’s a significant responsibility to be the primary coordinator and communicator of all that care. At the time, and even now for families, it was really challenging to go home with that level of medical technology and limited resources.”
Access to diagnostic testing and specialized care varies from country to country, and even within countries. In some places, genetic testing and at-home support aren’t readily available, and in others, they’re non-existent.9,10
The demands of care can touch every part of family life. Parents may put their careers on hold to be full-time caregivers, which can take a toll on their emotional and physical health. It can strain relationships and change routines. Siblings can grow up quickly in the presence of constant medical care.
“My daughter’s life has been a whole different experience,” Anne says. “At the age of four, she could tell you whether Tom needed suctioning or oxygen by the color of his lips.”
Despite the immense challenges that come with living with and caring for XLMTM, Chelsea says that the parents and families she’s met are some of the most amazing people she’s ever known.
Built from shared experience, this small but mighty community is always ready to welcome new families, advocate for their needs and offer guidance that only someone with a shared experience can give. “There’s a lot of love, there’s a lot of hope, there’s a lot of joy,” Chelsea says. “Those things are really important to the community to convey.”
It isn’t just those within the XLMTM community who are willing to offer a supportive hand, Anne says. “The people who are drawn to your life are people of huge generosity. You end up with great people in your life.”
Families living with XLMTM are passionate in describing the great joys their boys bring to their lives. Anne says she still remembers vividly the first time that Tom was able to hold his body up on his own, and Erin’s pride in Will graduating high school still shines just as brightly.
“It’s remarkable how much you see our lives from the outside,” Erin says. “It was intense, but we also had so much joy. One of the best blessings is every moment counted, every moment mattered, and that’s how we live our lives still.”
Without major advancements in care or viable treatment options, families living with XLMTM will continue to face specific challenges. Astellas’ work to help change that begins with understanding by listening to families, learning from clinicians and building trust within the community.
“First and foremost, we’re conducting a non-interventional study called EXCEL to advance our collective understanding of the natural history of XLMTM, and particularly how the lack of myotubularin affects different organs, including the liver,” Lucy says. “By closely following patients within their standard of care, we hope to uncover insights that not only inform future clinical trials but also help guide how we care for patients today.”
“Because diagnosis is a huge challenge for families, we’re also working with our Medical Affairs team and a committee of patients and healthcare professionals to develop an algorithm that can be used in hospitals,” Chelsea says. “So, if a baby is presenting with symptoms, the team can use this information to see whether they should test for XLMTM.”
As research continues, Astellas is working closely with the clinical and patient communities to explore ways to address the challenges of XLMTM. “Many people have never even heard of this condition and just by way of doing research, we’re bringing awareness to it,” Lucy says.
1 X-linked myotubular myopathy - symptoms, causes, treatment: Nord. National Organization for Rare Disorders. October 29, 2024. Accessed October 1, 2025. https://rarediseases.org/rare-diseases/x-linked-myotubular-myopathy/.
2 X-linked Myotubular Myopathy | Boston Children’s Hospital. Accessed October 1, 2025. https://www.childrenshospital.org/conditions/x-linked-myotubular-myopathy.
3 Therapeutics A. Looking ahead to a brighter future for XLMTM. XLMTM. Accessed October 20, 2025. https://www.xlmtm.com/.
4 Graham RJ, Muntoni F, Hughes I, et alMortality and respiratory support in X-linked myotubular myopathy: a RECENSUS retrospective analysis Archives of Disease in Childhood 2020;105:332-338. Accessed October 1, 2025, https://adc.bmj.com/content/105/4/332.
5 Duong T, Haselkorn T, Miller B, et al. A real-world analysis of the impact of X-linked myotubular myopathy on caregivers in the United States. Orphanet Journal of Rare Diseases. 2025;20(1). doi:10.1186/s13023-025-03583-w
6 XLMTM diagnosis versus other neuromuscular disorders. XLMTM. Accessed October 1, 2025. https://xlmtm.com/differential-diagnosis/.
7 North KN, Wang CH, Clarke N, et al. Approach to the diagnosis of congenital myopathies. Neuromuscul Disord. 2014;24(2):97-116. doi:10.1016/j.nmd.2013.11.003
8 Gangfuss A, Schmitt D, Roos A, et al. Diagnosing X-linked Myotubular Myopathy - A German 20-year Follow Up Experience. J Neuromuscul Dis. 2021;8(1):79-90. doi:10.3233/JND-200539.
9 Sacks NC, Healey BE, Cyr PL, et al. Costs and health resource use in patients with X-linked myotubular myopathy: insights from US commercial claims. J Manag Care Spec Pharm. 2021;27(8):1019-1026. doi:10.18553/jmcp.2021.20501
10 Souza PVS, Haselkorn T, Baima J, et al. A healthcare claims analysis to identify and characterize patients with suspected X-Linked Myotubular Myopathy (XLMTM) in the Brazilian Healthcare System. Orphanet J Rare Dis. 2024;19(1):188. Published 2024 May 7. doi:10.1186/s13023-024-03144-7
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