Traits

Traits linked to DMD

dystrophin

The Human Phenotype Ontology links 75 traits to DMD, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the musculoskeletal system

Trait	How often it is seen
Decreased lung function due to weak breathing muscles	Always
Difficulty walking up stairs	Always
Hamstring contractures	Always
Muscle weakness	Always
Flexed joint that cannot be straightened	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Progressive muscle weakness	Very often (80–99%)
Proximal neurogenic muscle weakness	Very often (80–99%)
Scoliosis	Very often (80–99%)
Excessive inward curvature of lower spine	Often (30–79%)
Muscle spasm	Often (30–79%)
Absent muscle dystrophin expression	Sometimes (5–29%)
EMG abnormality	Sometimes (5–29%)
Exercise-induced muscle cramps	Sometimes (5–29%)
Generalized muscle weakness	Sometimes (5–29%)
Loss of fat tissue in localized area	Sometimes (5–29%)
Muscle tissue disease	Sometimes (5–29%)
Thoracic kyphosis	Sometimes (5–29%)
Thoracic scoliosis	Sometimes (5–29%)
Gowers sign	Not recorded
Increased variability in muscle fiber diameter	Not recorded
Low muscle tone	Not recorded
Muscular dystrophy	Not recorded
Prominent swayback	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Delayed motor skills	Always
Loss of ability to walk	Always
Obstructive sleep apnea	Always
Toe walking	Always
Waddling gait	Always
Abnormal gait	Very often (80–99%)
Cognitive impairment	Very often (80–99%)
Delayed speech and language development	Very often (80–99%)
Global developmental delay	Very often (80–99%)
Motor delay	Very often (80–99%)
Specific learning disability	Very often (80–99%)
Falls	Often (30–79%)
Inability to walk	Sometimes (5–29%)
Decreased reflex response	Not recorded
Distal sensory impairment of all modalities	Not recorded
Intellectual disability, mild	Not recorded
Muscle twitch	Not recorded

Abnormality of limbs

Trait	How often it is seen
Inability to straighten knee	Always
Increased size of calf muscles	Always
Shortening of the achilles tendon	Always
Abnormality of the lower limb	Often (30–79%)
Abnormality of the shoulder girdle musculature	Sometimes (5–29%)
Dropped arches	Sometimes (5–29%)
Quadriceps weakness	Sometimes (5–29%)
Elbow flexion contracture	Rarely (1–4%)
Calf muscle pseudohypertrophy	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Increased left ventricular end-diastolic volume	Always
Disease of the heart muscle	Very often (80–99%)
Left ventricular systolic dysfunction	Very often (80–99%)
Stretched and thinned heart muscle	Very often (80–99%)
Abnormal heart rate	Often (30–79%)
Cardiac failure	Often (30–79%)
Left ventricular hypertrophy	Sometimes (5–29%)
Abnormal EKG	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Stiff lung or chest wall causing decreased lung volume	Always
Respiratory function loss	Very often (80–99%)
Exertional breathlessness	Often (30–79%)
Orthopnea	Often (30–79%)
Respiratory failure	Not recorded
Slow breathing	Not recorded

Laboratory abnormality

Trait	How often it is seen
Elevated blood creatine phosphokinase	Always
Elevated circulating CK-MB concentration	Always
Abnormal urinary color	Very often (80–99%)
Myoglobinuria	Very often (80–99%)
Fluid retention	Often (30–79%)
High liver enzymes	Often (30–79%)

Constitutional symptom

Trait	How often it is seen
Decreased ability to exercise	Very often (80–99%)
Muscle ache	Very often (80–99%)
Fatigue	Often (30–79%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Thromboembolic stroke	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Sometimes (5–29%)

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to DMD and how often each is seen. Find out more at hpo.jax.org.

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