What Is Muscular Dystrophy? An Australian Guide

What is muscular dystrophy? An Australian guide

Ask most Australians what muscular dystrophy is and they will describe Duchenne — a boy, diagnosed young, in a wheelchair by his teens. That picture is accurate for one type, and it is the type the public awareness campaigns are built around, and it accounts for a minority of people living with muscular dystrophy in this country.

Muscular dystrophy is a group of more than thirty genetically distinct conditions that share one feature: a gene fault causes muscle fibres to break down faster than the body can repair them. Beyond that shared mechanism, the differences are enormous. Some types begin at birth and some at sixty. Some are inherited from one parent, some from both, some arise new in a family. Some affect the heart more than the limbs. Some weaken the face and shoulders and never touch the legs. The most common adult form is a multisystem condition that causes cataracts, diabetes and cardiac arrhythmias alongside the weakness, and most people have never heard of it.

Muscular Dystrophy Foundation Australia, the national peak body, states that more than 40,000 Australians live with muscular dystrophy and similar rare conditions, within a wider category of more than 75 neuromuscular conditions.

So the first and most important thing in this guide is this: which type somebody has decides almost everything — the trajectory, the surveillance they need, what their children’s risk is, what treatment exists, and what support will be required and when. “Muscular dystrophy” on its own is not a useful amount of information, and a person who only knows that much about their own diagnosis should ask for more.

This guide covers what is happening in the muscle, the main types and how they differ, what they have in common, the Australian numbers, and the handful of things muscular dystrophy is confused with. Each major type then has a guide of its own.

What is actually happening

Muscle fibres are large cells under constant mechanical stress. Contracting and relaxing damages them microscopically, and a healthy muscle repairs that damage continuously. The structural proteins that hold the fibre together, anchor it to the surrounding tissue, and protect the membrane during contraction are what make that possible.

In muscular dystrophy, a gene fault means one of those proteins is absent, reduced or malformed. The fibre is damaged by ordinary use faster than it can be repaired. Over years, muscle fibres die and are replaced by fat and fibrous tissue. The muscle gets weaker, and on a scan or a biopsy you can see muscle being replaced by something that is not muscle.

Dystrophin is the best-known of these proteins and the one absent in Duchenne muscular dystrophy. The gene that makes it, on the X chromosome, is one of the largest in the human genome, which is part of why faults in it are relatively common. Absent dystrophin produces Duchenne; reduced or partially functional dystrophin produces the milder Becker muscular dystrophy. Other types involve other proteins — sarcoglycans, dysferlin, laminin, emerin, calpain — and the limb-girdle dystrophies alone encompass more than thirty genetically distinct subtypes.

Myotonic dystrophy works differently, and this matters because it is the most common adult form. The fault is a repeat expansion that produces toxic RNA, which interferes with how dozens of other genes are processed. That is why myotonic dystrophy is not confined to muscle: it affects the heart’s conduction system, the eyes, the endocrine system, the gut, the brain and sleep regulation. It is a multisystem disease that happens to include muscle weakness.

Two consequences follow from all of this, and they shape the whole of care.

Muscle, once lost, does not come back. Nothing currently available regrows lost muscle. Every intervention in muscular dystrophy either slows the loss, manages the consequences, or protects the organs that fail secondarily. Which makes early intervention worth much more than it looks.

The heart is a muscle. So is the diaphragm. In most types of muscular dystrophy, what shortens life is not limb weakness; it is cardiac and respiratory involvement. Both are now monitored and treated, and both are the reason survival has changed so much. See the heart and muscular dystrophy and breathing and muscular dystrophy.

The main types

Duchenne muscular dystrophy (DMD). X-linked, so it affects boys almost exclusively, with mothers as carriers and around 40 per cent of cases arising from a new mutation. Dystrophin is absent. Onset in early childhood, typically noticed as delayed walking, falls, difficulty with stairs, and calves that look unusually large. Australian research in New South Wales and the ACT put the incidence at 19.7 per 100,000 male live births, about 1 in 5,076. Corticosteroids, cardiac medication and ventilation have transformed the trajectory — more on that below, and in Duchenne muscular dystrophy.

Becker muscular dystrophy (BMD). The same gene, but dystrophin is reduced rather than absent. Onset later, progression slower, and the severity range is wide — some men are diagnosed in their thirties, and cardiac involvement can be significant even where limb weakness is mild. See Becker, limb-girdle and FSHD.

Myotonic dystrophy, types 1 and 2. The most common adult-onset form, with a worldwide prevalence of roughly 1 in 20,000 for type 1, though newborn screening data suggests the real figure is considerably higher and that many mild cases are never diagnosed. Autosomal dominant, so each child of an affected parent has a 50 per cent chance, and it shows anticipation — getting earlier and more severe through the generations. Features include distal weakness, myotonia (muscle that will not relax), facial weakness, cataracts, cardiac conduction disease, diabetes, daytime sleepiness and cognitive effects. See myotonic dystrophy.

Limb-girdle muscular dystrophy (LGMD). More than thirty genetic subtypes, inherited in both dominant and recessive patterns, affecting the shoulder and hip girdles first. Onset from childhood to middle age. The subtype matters because the cardiac and respiratory risk differs substantially between them.

Facioscapulohumeral muscular dystrophy (FSHD). Autosomal dominant, affecting the face, shoulder blades and upper arms, typically with striking asymmetry. Onset often in the teens or twenties. Progression is usually slow and life expectancy generally normal, though a minority are severely affected.

Emery-Dreifuss muscular dystrophy. Early contractures, slowly progressive weakness, and — the defining feature — serious cardiac conduction disease that frequently requires a pacemaker and which can be the first and most dangerous manifestation. This is a type where the cardiology matters more than the neurology.

Congenital muscular dystrophies. A group presenting at birth or in infancy with hypotonia and weakness, some with brain or eye involvement.

Oculopharyngeal muscular dystrophy (OPMD). Late onset, typically after 50, affecting the eyelids and swallowing.

Distal muscular dystrophies, affecting hands and feet first.

What they have in common

Despite the differences, a set of issues recurs across most types, and these are the things worth knowing regardless of diagnosis.

Progressive weakness, usually proximal first in the girdle types and distal first in myotonic and distal dystrophies.

Contractures. Muscles shorten when joints are not moved through full range, and in muscular dystrophy that happens early and matters a lot. Ankles, knees, hips, elbows and hands. Contracture prevention — stretching, splinting, standing, positioning — is unglamorous, under-prescribed, and one of the highest-value things physiotherapy offers.

Scoliosis, particularly after someone stops walking.

Cardiac involvement, which varies by type and is the leading cause of death in several. Surveillance is not optional and the schedule differs by diagnosis.

Respiratory involvement. Diaphragm and intercostal weakness, reduced cough, nocturnal hypoventilation before daytime breathlessness.

Swallowing difficulty, late in several types and early in OPMD and myotonic dystrophy.

Fatigue, which is pervasive and systematically dismissed.

Pain, from contractures, poor positioning and overuse of remaining muscle. Under-treated across the board.

And cognitive and learning effects in some types — a subset of boys with Duchenne have learning difficulties, autism or ADHD at higher rates than the general population, because dystrophin is also expressed in the brain, and myotonic dystrophy has its own cognitive profile.

The Australian numbers, and the thing that has changed

Here is the development that should reframe how Australia thinks about this group of conditions.

A 50-year retrospective cohort study of Duchenne muscular dystrophy in Australia, published in The Lancet Regional Health – Western Pacific in 2025 by Davidson and colleagues, followed 356 males with DMD born between 1958 and 2014, using records from a paediatric hospital linked to two adult tertiary hospitals.

Median survival rose from 18.2 years for those born before 1970 to 24.0 years for those born in the 1990s.

Over the same period, use of corticosteroids, ACE inhibitors, echocardiography and respiratory support all increased, and people using those treatments lived longer. The mean age at diagnosis fell from 6.4 years for those born before 1970 to 3.4 years for those born from 2010.

The authors’ conclusion is the part that matters for this website: as more people with Duchenne reach adulthood, Australia needs stronger clinical services and surveillance, particularly transitional and adult care. Monash University, where the lead author is based, headlined its summary of the work bluntly — science is rewriting the Duchenne lifespan, and care has to catch up.

That is the central fact about muscular dystrophy care in Australia in 2026. The medicine worked. Children who would have died at eighteen are now adults in their twenties and thirties, with jobs, relationships, degrees and tenancies — and the system around them was designed on the assumption they would not be here. It is covered properly in Duchenne into adulthood.

The rest of the Australian picture:

Two rows there deserve attention.

Parents raised concerns at 1.8 years and diagnosis came at 4.8 years. A three-year gap, in a condition where early steroid treatment changes the trajectory. That gap is the clearest avoidable failure in Australian muscular dystrophy care and it is covered in Duchenne muscular dystrophy.

And Australia does not have good national data. The incidence study covered New South Wales and the ACT only, and its authors said national applicability needed further evaluation. A 2025 scoping review of the Australian burden of DMD found the evidence base limited and called for more research. There is no comprehensive national registry giving current prevalence by type.

What muscular dystrophy is confused with

Spinal muscular atrophy (SMA). Not a muscular dystrophy — the problem is in the motor neurones, not the muscle fibre. It matters because SMA now has effective disease-modifying treatment, and because the inheritance pattern and prognosis differ entirely.

Motor neurone disease. Also a nerve condition rather than a muscle one, usually adult-onset, usually not inherited, and much faster. People do confuse them. See what is motor neurone disease.

Myasthenia gravis, an autoimmune condition causing fatigable weakness, which is treatable.

Inflammatory myopathies — polymyositis, dermatomyositis, inclusion body myositis. Some are treatable with immunosuppression, which is why a muscle biopsy or antibody testing is sometimes needed before a dystrophy is assumed.

Metabolic and mitochondrial myopathies, some of which respond to specific treatment.

Statin-induced myopathy, worth noting because statins can also unmask or worsen a genetic muscle condition, and should generally be avoided in myotonic dystrophy.

Cerebral palsy, in a toddler with delayed walking and an abnormal gait. This happens, and it is one reason the diagnostic delay in Duchenne is as long as it is. A boy with motor delay should have a creatine kinase (CK) blood test — it is cheap, it is available in any pathology lab, and in Duchenne it comes back enormously elevated. The single most useful sentence in this guide for a parent of a late-walking boy is: ask for a CK test.

Treatment: where things actually stand

Honesty is worth more than optimism here, because muscular dystrophy is a field where the gap between what is reported and what is available in an Australian clinic is unusually wide.

What has genuinely changed outcomes, and is available:

Corticosteroids in Duchenne. Prednisolone or deflazacort, which slow the loss of muscle strength and prolong walking. This is the single biggest intervention in DMD and it comes with real costs — bone fragility, weight gain, growth suppression, behavioural effects — which are managed rather than avoided. See steroids, bones and scoliosis.

Cardiac medication. ACE inhibitors or angiotensin receptor blockers, recommended by age 10 in boys with DMD, started before there is any symptom, to protect the heart. This is prophylactic treatment of an organ that has not yet failed, and it is one of the reasons the survival curves moved.

Non-invasive ventilation and cough assist. Nocturnal ventilation started on defined thresholds, later extended into the day.

Multidisciplinary clinic care, and surveillance done to a schedule rather than when something goes wrong.

Spinal surgery for progressive scoliosis, and contracture management throughout.

What exists internationally and is harder to access here. Exon-skipping therapies, which target specific mutations and suit only a minority of people with DMD; ataluren, for nonsense mutations; and gene therapy, which has been approved in some jurisdictions and remains the subject of active debate about benefit, risk and cost. Australian availability, eligibility and subsidy for these change, and anything written about them dates quickly. Ask your neuromuscular clinic what is currently accessible for your specific mutation, because the answer is mutation-dependent and time-dependent, and general articles — including this one — are not a reliable guide to it.

What does not exist. Anything that regrows lost muscle, and any cure for any type.

Where to start

Get the specific diagnosis in writing, with the gene and the variant. For almost every purpose that follows — surveillance, family risk, treatment eligibility, funding — the subtype is what matters.

Get into a neuromuscular clinic. Multidisciplinary clinic attendance is the thing most associated with receiving the interventions that work, and in Australia these are concentrated in capital cities, attached to major hospitals, with paediatric and adult services usually separate.

Contact your state muscular dystrophy organisation. The national peak body is Muscular Dystrophy Foundation Australia, whose members are the state and territory organisations — Muscular Dystrophy Australia, Muscular Dystrophy Queensland, Neuromuscular WA and their counterparts — several of which are registered NDIS providers and run equipment, camp, counselling and advocacy programmes.

Get genetic counselling, free through state genetic services, for the person and their relatives. Inheritance patterns differ by type and the implications for siblings and children are specific. See families, carriers and genetics.

And apply to the NDIS. Duchenne and Becker muscular dystrophy are named on NDIS List B. See muscular dystrophy and the NDIS.