Introduction

Understanding centronuclear myopathy

Centronuclear myopathy (CNM) is a group of rare, neuromuscular conditions that mainly affect the muscles used for movement. CNM is an inherited condition caused by a change (mutation) in a gene that is passed down from one or both parents. The three main types of CNM are:¹

• X-linked myotubular myopathy (XLMTM): Caused by a mutation in the MTM1 gene, it usually affects  young males and can be very severe
• Autosomal dominant CNM: often due to changes in the DNM2 gene, it tends to be milder and may appear later in life
• Autosomal recessive CNM: Linked to genes such as BIN1, RYR1 or TTN, can vary greatly in how severe it is

Each type of CMN causes issues with the strength and function of skeletal muscles. These muscles are responsible for movement, breathing, and sometimes swallowing. It can appear at birth, in childhood, or even in early adulthood. You may have heard other names for CNM, like myotubular myopathy, which refers to one of the more severe types found in newborns.

If you or a loved one is living with CNM, you might already be familiar with symptoms. Including muscle weakness, poor muscle tone (floppiness), developmental delays (like sitting or walking), and sometimes breathing difficulties. Currently, there is no cure for CNM, but there are many ways to manage the condition and improve the quality of life. This includes physiotherapy, orthopaedic treatments, and various assistive technologies.²

Physiotherapy

Physiotherapy is a type of treatment that helps improve how your body moves and functions. It is also one of the key treatments for people living with CNM. It does not stop the condition from progressing, but it helps maintain function, flexibility, and comfort for as long as possible.

Why is physiotherapy important?

In CNM, muscle weakness can lead to limited movement and stiffness in the joints. Without regular movement, joints can become tight (a problem called contractures), and muscles may become even weaker. Physiotherapy helps people with CNM with safe movement and gentle stretching. This helps to maintain flexibility and function.³

Physiotherapists can support young children with CNM with their positioning. Supporting parents with handling and encouraging normal development..For older children and adults, physio exercises depend on the person's strength and daily needs. Some people may need physiotherapy for just a few weeks to deal with a short-term problem. Others may need it for several months or even years to help manage long-term symptoms of a chronic condition.

What does physiotherapy involve?

Physiotherapy involves a physiotherapist who helps you move specific muscles of your body. They guide you through specific exercises and movements. The exercises are tailored to each person and often include:

• Stretching - to maintain joint flexibility and reduce tightness
• Strengthening exercises that are done gently and safely to avoid fatigue
• Postural support to prevent spinal deformities like scoliosis
• Chest physiotherapy helps clear mucus from the lungs. It's especially useful for people with weak breathing muscles.
• Hydrotherapy, or water-based exercises Doing the excersises in water can be particularly helpful due to the reduced strain on muscles in water

Physiotherapy is usually done as an outpatient treatment, meaning you do not need to stay in a hospital or clinic. Sometimes, it can also be done through a virtual appointment, using a video call or phone call, known as telehealth.

It is very important that exercises are introduced carefully. Overexerting the muscle can cause more harm than good, especially in people with certain genetic forms of CNM that are sensitive to fatigue.⁴

Physiotherapists also track your progress over time, adjusting the plan as your needs change. A regular routine, even a light one, can greatly help keep your muscles working well.

Orthopaedic management in CNM

As muscles weaken and joints become less mobile, some people with CNM may develop orthopaedic problems. These can include contractures (tight joints), scoliosis (curving of the spine), hip dislocations, or foot deformities.

Common orthopaedic issues

• Contractures happen when muscles are too weak to fully move or straighten a joint. They are often seen in the ankles, knees, elbows, or hips
• Scoliosis or a curve in the spine, can develop, especially in people with more severe forms of CNM. It can worsen with age and affect breathing in some cases
• Hip problems, like dislocation or subluxation (partial dislocation), are more common in early-onset CNM
• Foot deformities, such as high arches or clubfoot, can affect walking and balance

Management and treatment

Treatment aims to reduce discomfort, maintain mobility, and delay worsening of these problems.  Often, physiotherapists try physiotherapy and splinting first. Physiotherapists may consider surgery if contractures are severe or interfere with daily life.

Orthopaedic management may involve:

• Stretching and splinting, including ankle-foot orthoses (AFOs) to support walking
• Bracing is used for scoliosis in younger children or those not ready for surgery
• Surgical correction ( such as tendon release or spinal fusion) if non-surgical approaches are no longer effective

It is essential to work closely with an orthopaedic specialist who understands neuromuscular conditions like CNM. Surgery may not always be the best option for everyone.  It is usually only recommended when necessary.⁵

Assistive technologies and devices

What is assistive technology?

Assistive technology refers to any products or services that help you easily carry out daily activities. It includes items like wheelchairs, aids, stair lifts, hearing aids and speech-generating devices. Almost everyone uses some form of assistive technology at some stage in their life.  Assertive technology helps people interact with the world. Since the technology helps improve mobility, thinking, and learning.

Mobility aids

Mobility devices can range from walking frames/sticks to manual or powered wheelchairs. The right aid depends on your strength, balance, and endurance. For example:

• Walkers or rollators may help if you can walk but need some extra support
• Manual wheelchairs might be used for longer distances
• Power wheelchairs can be helpful for those with significant weakness or fatigue

Using a wheelchair is not a sign of giving up. It allows you to move around and save your energy for activities you enjoy.⁶

Respiratory support

In CNM, breathing muscles may be weak, especially in early-onset forms. Some people need ventilatory support, either full-time or just overnight. A respiratory team will assess your lung function regularly and recommend equipment if needed.⁷ For example:

• Non-invasive ventilation (NIV), such as a BiPAP machine through a mask, is often used at night
• Cough assist devices to help clear secretions from the lungs
• Pulse oximeters and capnography for monitoring oxygen and carbon dioxide levels at home

Feeding and communication aids

Sometimes, the muscles used for swallowing can weaken. This makes eating and drinking difficult. Speech and language therapists (SLTs) can assist with feeding techniques. They can also suggest the use of feeding tubes if necessary.

SLTs also support communication, especially in children who may struggle with speech. Sometimes, the muscles used for swallowing can weaken. This makes eating and drinking difficult. Speech and language therapists (SLTs) can assist with feeding techniques. They can also suggest the use of feeding tubes if necessary.⁸

Home adaptations and daily living aids

Occupational therapists can assess your home and suggest changes to make moving around the house easier. This might include:

• Ramps, grab rails, and stairlifts
• Adapted bathrooms and kitchens
• Special chairs or beds
• Modified utensils for eating or writing

 Technology is quickly advancing. Many people with CNM find smart home tools helpful. They also benefit from powered wheelchairs with custom controls and eye-tracking devices for communication.

Psychological and social support

Managing a rare condition like CNM goes beyond physical symptoms. Living with chronic illness, especially from a young age, can affect your emotional well-being, self-esteem, and relationships. Many families experience stress, uncertainty, or social isolation. It is important to understand that support for emotional and mental health is just as important as physical treatment.

Counsellors, psychologists, and peer support groups can help you talk about your feelings. They allow you to find coping strategies and meet with others facing similar challenges. Joining organisations like  Muscular Dystrophy UK and Myotubular Trust, or even CNM-focused Facebook groups, can help you find valuable support.⁹

Looking to the future

Although there is no cure yet, there is growing hope..Researchers are actively studying the genetic causes of CNM. Ongoing clinical trials are testing gene therapies and other treatments. These aim to target the root of the condition, not just its symptoms.⁵

In the meantime, physiotherapy, orthopaedic care, and assistive technologies are essential tools to help you live fully, comfortably, and independently.

Never hesitate to ask questions, advocate for your needs, and seek second opinions. You are the most important person when it comes to your own care.

Summary

If you or your loved one has centronuclear myopathy (CNM), you may be living with muscle weakness, delayed movement, and sometimes breathing or feeding difficulties. While there is no cure, there are ways to make life easier and more comfortable. Physiotherapy helps keep joints flexible. It also prevents muscle tightness and supports good posture and breathing. It is tailored to your needs and changes over time. Orthopaedic care is also important, especially if you develop joint problems, spine curvature, or foot issues. The treatment may involve braces, splints, or surgery, depending on the severity of the condition. Assistive technologies such as wheelchairs, ventilators, and communication devices can greatly improve independence. Tools that help with movement, speaking, eating, or adjusting your home can make daily life easier. 

 Remember, you are not alone on this journey. Support groups and mental health professionals can offer emotional support, helping you cope with the challenges of living with CNM. Managing CNM is about building a team around you to support your body, mind, and well-being.