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Mappings

MONDO

MONDO:0010679 Duchenne muscular dystrophy

Orphanet's cross-reference table lists "MONDO:0010679 | Exact" for the Duchenne muscular dystrophy record.

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Inheritance

1

X-linked recessive inheritance HP:0001419

Orphanet classifies Duchenne muscular dystrophy as an X-linked recessive disorder.

X-linked recessive inheritance

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"X-linked recessive"

The Orphanet inheritance section directly states the X-linked recessive mode of inheritance for Duchenne muscular dystrophy.

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Subtypes

2

Classic Duchenne

Complete absence of dystrophin, onset by age 5, wheelchair-dependent by early teens.

Intermediate DMD

Partial dystrophin expression, intermediate severity between DMD and Becker.

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Mechanistic Hypotheses

1

Canonical Dystrophin Loss and Membrane Fragility Model

canonical_dystrophin_loss_membrane_fragility_model CANONICAL

Out-of-frame DMD variants abolish functional dystrophin, the cytoskeletal link between cytoplasmic F-actin and the sarcolemmal dystrophin-glycoprotein complex (DGC). Without dystrophin the DGC is destabilized at the sarcolemma, leaving muscle fibers vulnerable to contraction-induced mechanical injury, calcium influx through stretched/damaged membrane, and activation of calcium-dependent proteases. Repeated cycles of fiber necrosis, satellite-cell-driven regeneration, chronic inflammation, and progressive fibro-fatty replacement of muscle ultimately exhaust regenerative capacity, producing the characteristic progressive proximal weakness, cardiomyopathy, respiratory failure, and short life expectancy of Duchenne muscular dystrophy. Exon-skipping and gene-replacement therapies that restore even partial dystrophin expression provide interventional validation of this canonical chain.

Deep research

Falcon citations 40 citations 2026-05-23T19:03:11.288051

Show evidence (1 reference)

PMID:16770791 SUPPORT Human Clinical

"The severe Duchenne and milder Becker muscular dystrophy are both caused by mutations"

Canonical mechanism review used as the seed reference for the hypothesis-search deep-research run.

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Discussions and Knowledge Gaps

1

Does restored dystrophin or microdystrophin expression reverse established skeletal-muscle and myocardial fibrosis in DMD, or does it mainly stabilize sarcolemmal injury before fibrotic remodeling becomes self-sustaining?

KNOWLEDGE GAP OPEN gap_dmd_microdystrophin_fibrosis_reversal

Attached to

pathophysiology#Dystrophin Deficiency pathophysiology#Sarcolemmal Fragility pathophysiology#Fibrofatty Muscle Replacement pathophysiology#Myocardial Fibrosis

The entry already captures dystrophin loss, membrane fragility, chronic degeneration, and fibrofatty replacement. Recent human engineered-muscle work suggests that membrane stabilization and profibrotic signaling can decouple, making the reversibility of established fibrosis a distinct therapeutic knowledge gap rather than a simple proxy for dystrophin expression.

Proposed experiments

Fibrotic patient-derived DMD MYOrganoid microdystrophin rescue assay

patient-derived organoid perturbation experiment

exp_dmd_fibrotic_myorganoid_microdystrophin_rescue

Build patient-derived iPSC skeletal-muscle MYOrganoids with a fibroblast niche and induced fibrotic maturation, deliver microdystrophin before or after fibrotic priming, and compare membrane stability, contractile fatigue, and extracellular-matrix remodeling.

Model systems

Patient-derived DMD skeletal-muscle MYOrganoid with fibroblast niche

Three-dimensional iPSC-derived skeletal-muscle organoid containing fibroblasts so dystrophic membrane injury, repeated-contraction fatigue, and profibrotic muscle-fibroblast signaling can be measured in the same standardized human model.

ORGANOID namo:Organoid link

human link

skeletal muscle tissue link

skeletal muscle cell fibroblast link

Perturbations

Microdystrophin gene transfer

pathophysiology#Dystrophin Deficiency

AAV-like microdystrophin delivery or matched genetic rescue used to restore dystrophin-family membrane support in the engineered tissue.

gene therapy link

Fibrotic niche priming

pathophysiology#Fibrofatty Muscle Replacement

Fibroblast-containing dystrophic culture conditions, optionally with TGF-beta pathway stimulation, used to establish a profibrotic baseline before rescue.

extracellular matrix organization link

Readouts

Sarcolemmal membrane stability

pathophysiology#Sarcolemmal Fragility

Dye-exclusion or membrane-leak readout after eccentric contraction.

membrane permeability assay

Direction: NEGATIVE

Contractile force and fatigue resistance

pathophysiology#Progressive Muscle Degeneration

Electrical-stimulation force and fatigue readouts in matched tissue rings.

contractility assay

Direction: NEGATIVE

Profibrotic extracellular-matrix signaling

pathophysiology#Fibrofatty Muscle Replacement

Collagen, fibronectin, and TGF-beta-responsive transcriptional readouts interpreted as persistence or resolution of fibrotic remodeling.

extracellular matrix organization link

single-cell transcriptomic profiling extracellular matrix immunostaining

Direction: NEGATIVE

Controls

Isogenic corrected MYOrganoid

DMD-corrected tissue carrying the same genetic background.

Empty-vector DMD MYOrganoid

Dystrophic organoid receiving vector or delivery control without microdystrophin.

Decision criterion

Reversal is supported if delayed microdystrophin rescue improves membrane stability and contractile fatigue while reducing profibrotic extracellular-matrix readouts toward isogenic-corrected levels. Stabilization-only is supported if membrane and force readouts improve but fibrotic signaling remains elevated.

Would support

pathophysiology#Sarcolemmal Fragility pathophysiology#Fibrofatty Muscle Replacement pathophysiology#Myocardial Fibrosis

Show evidence (3 references)

DOI:10.1038/s41536-025-00445-8 SUPPORT In Vitro

"recapitulating critical hallmarks of DMD, such as fibrosis and muscle dysfunction"

Provides the recent human organoid precedent for testing DMD fibrosis and muscle dysfunction in a fibroblast-containing engineered tissue.

DOI:10.1038/s41536-025-00445-8 SUPPORT In Vitro

"it fails to reduce profibrotic signaling"

Motivates the specific knowledge gap: restored microdystrophin activity may not be sufficient to extinguish established fibrotic signaling.

+ 1 more reference

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Pathophysiology

14

DMD Loss-of-Function Variants

Duchenne muscular dystrophy is caused by pathogenic variants in the X-linked DMD gene that abolish or severely reduce functional dystrophin. Out-of-frame deletions, duplications, nonsense, frameshift, and splice-disrupting variants typically produce the Duchenne phenotype, whereas in-frame variants that preserve partially functional dystrophin more often produce Becker or intermediate dystrophinopathy.

Downstream

Dystrophin Deficiency Duchenne-associated DMD variants disrupt the reading frame or truncate the transcript, leaving little or no functional dystrophin in striated muscle.

Show evidence (2 references)

PMID:23650001 SUPPORT Human Clinical

"Duchenne/Becker muscular dystrophies (DMD/BMD) lead to progressive irreversible muscle deterioration caused by recessive mutations in the dystrophin encoding gene (Xp21.1). Approximately 60% of mutations are deletions, 10% are duplications and the remaining 30% are point mutations."

This human molecular cohort summary supports DMD as the causal gene and gives the major mutation classes that initiate the dystrophinopathy path.

PMID:16770791 SUPPORT Human Clinical

"The severe Duchenne and milder Becker muscular dystrophy are both caused by mutations in the DMD gene. This gene codes for dystrophin, a protein important for maintaining the stability of muscle-fiber membranes."

The Leiden mutation database review links DMD variants to dystrophin and membrane-stability phenotypes across Duchenne and Becker dystrophinopathy.

Dystrophin Deficiency

Mutations in the DMD gene cause absent or dysfunctional dystrophin protein. Dystrophin links the cytoskeleton to the extracellular matrix in muscle fibers and cardiomyocytes, providing structural stability during contraction.

Skeletal Muscle Fiber link Cardiac Muscle Cell link

Plasma Membrane Organization link ↓ DECREASED

Downstream

Dystrophin-Glycoprotein Complex Destabilization Loss of dystrophin disconnects cytoskeletal and membrane elements, destabilizing the dystrophin-glycoprotein complex at the sarcolemma.

Show evidence (2 references)

PMID:37435300 SUPPORT Human Clinical

"The identification of the dystrophin gene as central to DMD pathogenesis has led to the understanding of the muscle membrane and the proteins involved in membrane stability as the focal point of the disease."

Review confirms dystrophin gene mutations cause membrane instability as the central pathogenic mechanism.

PMID:23620650 SUPPORT Human Clinical

"The genetic cause of DMD is an x-chromosomal mutation of the dystrophin gene. Dystrophin mechanically stabilises myofibres by linking the cytoskeleton to the basal lamina through the dystroglycan complex."

This mechanistic review ties the causal DMD mutation to loss of the dystrophin mechanical-stability function in myofibres.

Dystrophin-Glycoprotein Complex Destabilization

The dystrophin-glycoprotein complex normally stabilizes cardiac and skeletal muscle sarcolemma by coupling the cytoskeleton, plasma membrane, and extracellular matrix. Dystrophin loss destabilizes this complex and leaves striated muscle cells vulnerable to contraction-associated membrane damage.

Skeletal Muscle Fiber link Cardiac Muscle Cell link

Plasma Membrane Organization link ↓ DECREASED

Downstream

Sarcolemmal Fragility DGC destabilization causes fragile, leaky striated-muscle membranes during contraction.

Cardiac Myocyte Injury The same DGC fragility mechanism injures dystrophin-deficient cardiomyocytes and contributes to progressive cardiac remodeling.

Show evidence (1 reference)

PMID:15117830 SUPPORT Model Organism

"The dystrophin glycoprotein complex (DGC) is a specialization of cardiac and skeletal muscle membrane. This large multicomponent complex has both mechanical stabilizing and signaling roles in mediating interactions between the cytoskeleton, membrane, and extracellular matrix."

This defines the DGC as the mechanical and signaling scaffold disrupted downstream of dystrophin deficiency.

Sarcolemmal Fragility

Unprotected sarcolemma undergoes contraction-induced microtears and loss of membrane integrity, releasing intracellular enzymes and creating the entry point for downstream calcium injury.

Skeletal Muscle Fiber link Cardiac Muscle Cell link

Plasma Membrane Organization link ↓ DECREASED

Downstream

Calcium Influx Loss of sarcolemmal integrity permits pathologic calcium entry into dystrophin-deficient muscle cells.

TRPC/SOCE-mediated Calcium Entry Membrane instability activates TRPC channels and STIM1/ORAI1 store-operated calcium entry as a parallel route of pathologic calcium entry into dystrophic myofibers.

Elevated Creatine Kinase Membrane leak and myofiber injury release CK into serum.

Show evidence (1 reference)

PMID:15117830 SUPPORT Model Organism

"Animal models of DGC mutants have shown that destabilization of the DGC leads to membrane fragility and loss of membrane integrity, resulting in degeneration of skeletal muscle and cardiomyocytes."

This directly supports sarcolemmal fragility downstream of DGC destabilization.

Calcium Influx

Calcium enters dystrophin-deficient muscle cells through damaged membrane, contributing to hypercontraction, protease activation, and downstream myofiber necrosis.

Skeletal Muscle Fiber link Cardiac Muscle Cell link

Calcium Ion Transport Into Cytosol link ↑ INCREASED

Downstream

Myofiber Necrosis Calcium overload, membrane rupture, and contraction injury drive myofiber necrosis.

Show evidence (1 reference)

PMID:1497954 SUPPORT Other

"Partial failure of the pump would result in intracellular accumulation of calcium, hypercontractions of the sarcomeres, rupture of the cell membrane, massive influx of calcium and cell necrosis."

This classic calcium-hypothesis review links calcium accumulation, membrane rupture, calcium influx, and necrosis in DMD pathogenesis.

TRPC/SOCE-mediated Calcium Entry

A parallel pathologic calcium entry route in dystrophic muscle operating through transient receptor potential canonical (TRPC) cation channels and STIM1-ORAI1 store-operated calcium entry (SOCE) complexes. Genetic studies in mice show that activation of these channels alone is sufficient to recapitulate the dystrophic phenotype, and that inhibiting them ameliorates pathology in mdx and delta-sarcoglycan-deficient models. This mechanism operates downstream of the unstable sarcolemma but independently of direct membrane rupture as a route of calcium influx.

Skeletal Muscle Fiber link Cardiac Muscle Cell link

Store-Operated Calcium Entry link ↑ INCREASED Calcium Ion Transmembrane Transport link ↑ INCREASED

Downstream

Myofiber Necrosis Calcium overload via TRPC channels and STIM1-ORAI1 store-operated entry activates calcium-dependent proteases and mitochondrial permeability transition, driving myofiber necrosis independently of direct sarcolemmal rupture.

Show evidence (3 references)

PMID:19864620 SUPPORT Model Organism

"overexpression of transient receptor potential canonical 3 (TRPC3) and the associated increase in calcium influx resulted in a phenotype of muscular dystrophy nearly identical to that observed in DGC-lacking dystrophic disease models"

TRPC3 overexpression alone induces a dystrophic phenotype indistinguishable from genetic DGC loss, demonstrating TRPC-mediated calcium entry is sufficient to drive muscular dystrophy in vivo.

PMID:19864620 SUPPORT Model Organism

"transgene-mediated inhibition of TRPC channels in mice dramatically reduced calcium influx and dystrophic disease manifestations associated with the mdx mutation (dystrophin gene) and deletion of the delta-sarcoglycan (Scgd) gene."

Conversely, TRPC channel inhibition rescues dystrophic disease in mdx mice, establishing TRPC-mediated calcium influx as causal in DMD-relevant models.

PMID:26088163 SUPPORT Model Organism

"models with artificially elevated calcium in skeletal muscle manifest fulminant dystrophic-like disease, whereas models with enhanced calcium clearance or inhibited calcium influx are resistant to myofiber death and MD."

Reviews the genetic mouse evidence (including STIM1/ORAI1 and TRPC manipulations) that elevated cytosolic calcium alone is sufficient to drive dystrophic disease independent of membrane rupture.

Myofiber Necrosis

Repeated contraction-associated membrane injury causes skeletal myofiber necrosis, releasing damage signals that initiate inflammatory remodeling and repeated repair attempts.

Skeletal Muscle Fiber link

Downstream

Failed Satellite Cell Regeneration Continuous myofiber breakdown exceeds the compensatory capacity of satellite-cell proliferation.

Chronic Muscle Inflammation Necrotic muscle fibers trigger inflammatory mediators and immune-cell recruitment, sustaining a tissue-damage cycle.

Show evidence (1 reference)

PMID:23620650 SUPPORT Human Clinical

"Finally, the cellular integrity is unsustainable. Myofibre necrosis and inflammation lead to fibrotic tissue remodelling."

This supports myofiber necrosis as the immediate tissue-injury event that precedes inflammatory and fibrotic remodeling.

Failed Satellite Cell Regeneration

Satellite-cell proliferation attempts to repair ongoing dystrophic injury, but repeated necrosis outpaces regenerative capacity and leaves muscle loss progressively irreversible.

Skeletal Muscle Satellite Stem Cell link

Downstream

Progressive Muscle Degeneration Failed regenerative compensation allows irreversible loss of functional myofibers to accumulate over time.

Show evidence (1 reference)

PMID:23620650 SUPPORT Human Clinical

"In DMD, constant myofibre breakdown cannot be fully compensated for by satellite cell proliferation."

This supports failed satellite-cell compensation as a distinct event in the mutation-to-phenotype path.

Chronic Muscle Inflammation

Necrotic dystrophic muscle releases damage signals that recruit macrophages and amplify cytokine-mediated injury. Persistent inflammation links the primary membrane defect to fibrotic remodeling.

Macrophage link

Inflammatory Response link ↑ INCREASED

Downstream

Fibrofatty Muscle Replacement Persistent inflammation after necrosis promotes extracellular-matrix remodeling, fibrosis, and fatty replacement of muscle.

Show evidence (1 reference)

PMID:23620650 SUPPORT Human Clinical

"Calcium acts as a second messenger and activates a cascade of inflammatory processes."

This links calcium-overload injury to inflammatory signaling in the DMD causal path.

Fibrofatty Muscle Replacement

Chronic dystrophic injury activates fibroblasts and myofibroblast-like remodeling programs, depositing extracellular matrix and replacing functional muscle with fibrotic and fatty tissue. This tissue-level remodeling causes calf pseudohypertrophy and reduces contractile reserve.

Fibroblast link Adipocyte link

Extracellular Matrix Organization link ↑ INCREASED

Downstream

Progressive Muscle Degeneration Fibrosis and fat replacement remove functional contractile fibers and make weakness progressively irreversible.

Pseudohypertrophy of Calves Preferential fibrofatty remodeling of posterior calf muscles enlarges the calves despite loss of contractile muscle.

Show evidence (1 reference)

PMID:23620650 SUPPORT Human Clinical

"Inflammatory processes following muscular necrosis lead to fibrotic remodelling and finally fatty cell replacement."

This supports fibrofatty replacement as the downstream tissue-remodeling consequence of repeated necrosis and inflammation.

Progressive Muscle Degeneration

Without dystrophin, muscle fibers are susceptible to contraction-induced damage. Repeated cycles of degeneration and regeneration exhaust satellite cell pools, leading to fibrosis and fatty replacement of muscle tissue.

Skeletal Muscle Fiber link

Skeletal Muscle Contraction link ↓ DECREASED

Downstream

Progressive Muscle Weakness Loss of contractile fibers causes steadily worsening proximal weakness.

Gowers Sign Hip and thigh extensor weakness produces compensatory Gowers maneuver.

Respiratory Muscle Weakness The same progressive degeneration affects diaphragm and intercostal muscles, reducing ventilatory reserve and cough strength.

Show evidence (1 reference)

PMID:37435300 SUPPORT Human Clinical

"Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."

Review confirms progressive muscle wasting is a defining feature of DMD.

Respiratory Muscle Weakness

Progressive dystrophic degeneration of diaphragm and intercostal skeletal muscle reduces ventilation, cough effectiveness, and airway clearance, creating the respiratory-insufficiency branch of DMD.

Skeletal Muscle Fiber link

Skeletal Muscle Contraction link ↓ DECREASED

Downstream

Respiratory Insufficiency Diaphragmatic and intercostal weakness reduce ventilation and cough effectiveness.

Show evidence (1 reference)

PMID:37435300 SUPPORT Human Clinical

"Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."

The review identifies respiratory insufficiency as part of the progressive skeletal-muscle wasting phenotype.

Cardiac Myocyte Injury

Dystrophin deficiency in cardiomyocytes destabilizes the DGC, exposing the myocardium to membrane injury, calcium stress, and myocyte degeneration.

Cardiac Muscle Cell link

Cardiac Muscle Contraction link ↓ DECREASED

Downstream

Myocardial Fibrosis Injured dystrophin-deficient myocardium undergoes fibrotic remodeling.

Show evidence (2 references)

PMID:15117830 SUPPORT Model Organism

"Animal models of DGC mutants have shown that destabilization of the DGC leads to membrane fragility and loss of membrane integrity, resulting in degeneration of skeletal muscle and cardiomyocytes."

This supports cardiomyocyte injury as a direct consequence of DGC destabilization.

PMID:23620650 SUPPORT Human Clinical

"Mortality in DMD patients is often due to respiratory or cardiac problems."

This supports cardiac involvement as a life-limiting downstream branch of DMD tissue injury.

Myocardial Fibrosis

Recurrent cardiomyocyte injury and connective-tissue remodeling produce myocardial fibrosis, stiffening the myocardium and contributing to DMD cardiomyopathy.

Cardiac Muscle Cell link Fibroblast link

Extracellular Matrix Organization link ↑ INCREASED

Downstream

Cardiomyopathy Progressive myocardial fibrosis and dysfunction produce dilated cardiomyopathy.

Show evidence (1 reference)

PMID:23620650 SUPPORT Human Clinical

"Mortality in DMD patients is often due to respiratory or cardiac problems. In both body areas – the pulmonary and the pericardial connective tissues – the fibrotic changes in muscular dystrophy tend to be very severely expressed and they tend to influence strongly muscular function (74, 75)."

This supports myocardial and pericardial fibrosis as the downstream remodeling event that contributes to DMD cardiac disease.

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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

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Phenotypes

17

Cardiovascular 1

Cardiomyopathy VERY_FREQUENT Dilated cardiomyopathy (HP:0001644)

Dilated cardiomyopathy develops in nearly all patients by late teens

Show evidence (3 references)

PMID:37435300 SUPPORT Human Clinical

"Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."

Review confirms cardiomyopathy as a defining feature of DMD.

PMID:22463839 SUPPORT Human Clinical

"Cardiomyopathy is a consequence of Duchenne muscular dystrophy (DMD)."

Study confirms cardiomyopathy as a consequence of DMD.

ORPHA:98896 SUPPORT Other

"HP:0001638 | Cardiomyopathy | Very frequent (99-80%)"

Orphanet's HPO annotation supports cardiomyopathy as a very frequent phenotype in DMD; the existing phenotype term captures the common dilated cardiomyopathy presentation more specifically.

Limbs 1

Pseudohypertrophy of Calves VERY_FREQUENT Calf muscle pseudohypertrophy (HP:0003707)

Fatty and fibrous tissue replacement gives appearance of enlarged calves

Show evidence (2 references)

PMID:23620650 SUPPORT Human Clinical

"In DMD this phenomenon is often first seen in the posterior calf musculature, which is prone to overtraining because of its function as anti-gravity stabilizer (Fig. 1)."

The fibrosis review directly supports posterior calf involvement as an early fibrofatty remodeling site in DMD.

ORPHA:98896 PARTIAL Other

"HP:0008981 | Calf muscle hypertrophy | Very frequent (99-80%)"

Orphanet records very frequent calf enlargement using HP:0008981. This supports the calf-enlargement phenotype, while this entry keeps the more precise DMD pseudohypertrophy term because the modeled mechanism is fibrofatty replacement rather than true muscle hypertrophy.

Metabolism 1

Elevated Creatine Kinase VERY_FREQUENT Elevated circulating creatine kinase concentration (HP:0003236)

Often 10-100x normal, detectable from birth

Show evidence (2 references)

PMID:34626608 SUPPORT Human Clinical

"the creatine kinase test showed good accuracy in screening for cases of Duchenne Muscular Dystrophy and may be a useful alternative in the early diagnosis of the disease followed by confirmatory genetic testing."

Systematic review confirms CK testing has good diagnostic accuracy for DMD screening.

ORPHA:98896 SUPPORT Other

"HP:0003236 | Elevated circulating creatine kinase concentration | Very frequent (99-80%)"

Orphanet classifies elevated circulating creatine kinase as a very frequent DMD phenotype.

Musculoskeletal 6

Progressive Muscle Weakness VERY_FREQUENT Progressive muscle weakness (HP:0003323)

Proximal muscles affected first, onset typically 2-5 years

Show evidence (2 references)

PMID:37435300 SUPPORT Human Clinical

"Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."

Review confirms progressive skeletal muscle wasting as a defining feature of DMD.

ORPHA:98896 SUPPORT Other

"HP:0003323 | Progressive muscle weakness | Very frequent (99-80%)"

Orphanet's curated HPO annotation independently supports progressive muscle weakness as a very frequent DMD phenotype.

Gowers Sign VERY_FREQUENT Gowers sign (HP:0003391)

Using hands to push up from floor due to proximal weakness

Show evidence (1 reference)

PMID:15106215 PARTIAL Human Clinical

"Improvements were seen in time taken to rise from the floor (Gowers' time), nine metres walking time, four-stair climbing time, ability to lift weights, leg function grade and forced vital capacity."

Cochrane review uses Gowers time as an outcome measure, confirming its clinical relevance in DMD.

Proximal Muscle Weakness VERY_FREQUENT Proximal muscle weakness (HP:0003701)

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0003701 | Proximal muscle weakness | Very frequent (99-80%)"

Orphanet's curated HPO annotation classifies proximal muscle weakness as very frequent in DMD.

Skeletal Muscle Atrophy VERY_FREQUENT Skeletal muscle atrophy (HP:0003202)

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0003202 | Skeletal muscle atrophy | Very frequent (99-80%)"

Orphanet's curated HPO annotation classifies skeletal muscle atrophy as very frequent in DMD.

Flexion Contracture VERY_FREQUENT Flexion contracture (HP:0001371)

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0001371 | Flexion contracture | Very frequent (99-80%)"

Orphanet's curated HPO annotation classifies flexion contracture as very frequent in DMD.

Scoliosis VERY_FREQUENT Scoliosis (HP:0002650)

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0002650 | Scoliosis | Very frequent (99-80%)"

Orphanet's curated HPO annotation classifies scoliosis as very frequent in DMD.

Nervous System 5

Motor Delay Motor delay (HP:0001270)

Orphanet records this phenotype as Very frequent (99-80%), but this entry does not normalize that frequency band pending primary-literature support.

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0001270 | Motor delay | Very frequent (99-80%)"

Orphanet records motor delay as a DMD phenotype and supplies a very-frequent frequency band; the frequency band is kept as source context rather than a normalized dismech assertion here.

Waddling Gait VERY_FREQUENT Waddling gait (HP:0002515)

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0002515 | Waddling gait | Very frequent (99-80%)"

Orphanet's curated HPO annotation classifies waddling gait as very frequent in DMD.

Delayed Speech and Language Development Delayed speech and language development (HP:0000750)

Orphanet records this phenotype as Very frequent (99-80%), but this entry does not normalize that frequency band pending primary-literature support.

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0000750 | Delayed speech and language development | Very frequent (99-80%)"

Orphanet records delayed speech and language development as a DMD phenotype and supplies a very-frequent frequency band; the frequency band is kept as source context rather than a normalized dismech assertion here.

Global Developmental Delay Global developmental delay (HP:0001263)

Orphanet records this phenotype as Very frequent (99-80%), but this entry does not normalize that frequency band pending primary-literature support.

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0001263 | Global developmental delay | Very frequent (99-80%)"

Orphanet records global developmental delay as a DMD phenotype and supplies a very-frequent frequency band; the frequency band is kept as source context rather than a normalized dismech assertion here.

Cognitive Impairment Cognitive impairment (HP:0100543)

Orphanet records this phenotype as Very frequent (99-80%), but this entry does not normalize that frequency band pending primary-literature support.

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0100543 | Cognitive impairment | Very frequent (99-80%)"

Orphanet records cognitive impairment as a DMD phenotype and supplies a very-frequent frequency band; the frequency band is kept as source context rather than a normalized dismech assertion here.

Respiratory 1

Respiratory Insufficiency VERY_FREQUENT Respiratory insufficiency (HP:0002093)

Due to respiratory muscle weakness, main cause of death

Show evidence (2 references)

PMID:37435300 SUPPORT Human Clinical

"Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."

Review confirms respiratory insufficiency as a defining feature of DMD.

ORPHA:98896 SUPPORT Other

"HP:0002093 | Respiratory insufficiency | Very frequent (99-80%)"

Orphanet classifies respiratory insufficiency as a very frequent DMD phenotype.

Other 2

Loss of ambulation VERY_FREQUENT Loss of ambulation (HP:0002505)

Major functional milestone in DMD progression; glucocorticoid treatment delays loss of walking ability.

Show evidence (1 reference)

DOI:10.1186/s13023-024-03217-7 SUPPORT Human Clinical

"The median age at loss of ambulation was 2.5 years later in DMD patients who received glucocorticoid treatment."

Large dystrophinopathy cohort reports loss of ambulation as a treatment-sensitive DMD progression milestone.

Specific Learning Disability Specific learning disability (HP:0001328)

Orphanet records this phenotype as Very frequent (99-80%), but this entry does not normalize that frequency band pending primary-literature support.

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"HP:0001328 | Specific learning disability | Very frequent (99-80%)"

Orphanet records specific learning disability as a DMD phenotype and supplies a very-frequent frequency band; the frequency band is kept as source context rather than a normalized dismech assertion here.

🧬

Genetic Associations

2

DMD pathogenic variants (Causative loss-of-function variants)

X-linked recessive

Show evidence (2 references)

DOI:10.1186/s13023-024-03217-7 SUPPORT Human Clinical

"The spectrum of identified variants included exonic deletions (66.6%), exonic duplications (10.7%), nonsense variants (10.3%), splice-site variants (4.5%), small deletions (3.5%), small insertions/duplications (1.8%), and missense variants (0.9%)."

This recent 2,097-patient dystrophinopathy cohort updates the DMD variant spectrum and supports the curated mutation-class distribution.

PMID:16770791 SUPPORT Human Clinical

"Currently, over 4700 mutations have been reported in the Leiden DMD mutation database, of which 91% are in agreement with this rule."

This supports the reading-frame rule as the major genotype-phenotype principle while acknowledging known exceptions.

LTBP4 modifier variants (Genetic modifier of DMD severity)

Show evidence (1 reference)

ORPHA:98896 SUPPORT Other

"LTBP4 | latent transforming growth factor beta binding protein 4 | hgnc:6717 | Modifying germline mutation in"

Orphanet's genes table lists LTBP4 with a modifying germline-mutation relationship for the Duchenne muscular dystrophy record.

💊

Treatments

10

Corticosteroids

Action: Pharmacotherapy NCIT:C15986

Agent: prednisone ↗ deflazacort ↗

Prednisone or deflazacort to slow muscle degeneration and prolong ambulation.

Show evidence (2 references)

PMID:15106215 SUPPORT Human Clinical

"There is evidence from randomised controlled studies that glucocorticoid corticosteroid therapy in Duchenne muscular dystrophy improves muscle strength and function in the short-term (six months to two years)."

Cochrane review confirms corticosteroids improve muscle strength and function in DMD.

PMID:22581531 SUPPORT Human Clinical

"Long-term corticosteroid treatment is effective in prolonging function but not in recovering lost function, and its early use seems appropriate."

Long-term follow-up study confirms corticosteroids prolong function in DMD.

Cardiac Management

Action: Pharmacotherapy NCIT:C15986

Agent: ACE inhibitor ↗ beta-adrenergic antagonist ↗

ACE inhibitors and beta-blockers for cardiomyopathy prevention and treatment.

Show evidence (2 references)

PMID:22463839 SUPPORT Human Clinical

"Treatment with ACE inhibitor or ACE inhibitor plus BB resulted in significant improvement compared to pretherapy."

Study demonstrates ACE inhibitors improve cardiac function in DMD patients.

PMID:19167641 SUPPORT Human Clinical

"In this study, the combination of an ACE inhibitor and a beta-blocker had a beneficial effect on long-term survival of DMD patients with heart failure."

Study shows ACE inhibitor plus beta-blocker combination improves survival in DMD.

Respiratory Support

Action: supportive care MAXO:0000950

Non-invasive ventilation as respiratory function declines.

Eteplirsen (Exon 51 Skipping)

Action: Pharmacotherapy NCIT:C15986

Agent: eteplirsen ↗

Phosphorodiamidate morpholino antisense oligonucleotide that induces skipping of DMD exon 51, restoring the reading frame in patients with deletions amenable to exon 51 skipping and producing internally truncated but functional dystrophin.

Show evidence (1 reference)

PMID:29752304 SUPPORT Human Clinical

"In treated patients vs untreated controls, Western blot analysis of dystrophin content demonstrated an 11.6-fold increase (p = 0.007), and PDPF analysis demonstrated a 7.4-fold increase (p < 0.001)."

Clinical study demonstrates eteplirsen induces dystrophin production in DMD patients.

Golodirsen (Exon 53 Skipping)

Action: pharmacotherapy MAXO:0000058

Agent: golodirsen ↗

Phosphorodiamidate morpholino antisense oligonucleotide that induces skipping of DMD exon 53, restoring the reading frame in patients with deletions amenable to exon 53 skipping.

Show evidence (1 reference)

PMID:32139505 SUPPORT Human Clinical

"muscle biopsies from golodirsen-treated patients showed increased exon 53 skipping, dystrophin production, and correct dystrophin sarcolemmal localization."

SKIP-NMD trial shows golodirsen induces exon 53 skipping and increased sarcolemmal dystrophin in DMD patients amenable to exon 53 skipping.

Viltolarsen (Exon 53 Skipping)

Action: pharmacotherapy MAXO:0000058

Agent: viltolarsen ↗

Phosphorodiamidate morpholino antisense oligonucleotide that induces skipping of DMD exon 53, restoring the reading frame in patients with deletions amenable to exon 53 skipping.

Show evidence (1 reference)

PMID:32453377 SUPPORT Human Clinical

"After 20 to 24 weeks of treatment, significant drug-induced dystrophin production was seen in both viltolarsen dose cohorts"

Phase 2 RCT shows viltolarsen induces de novo dystrophin production in DMD patients amenable to exon 53 skipping.

Ataluren Stop-Codon Readthrough Therapy

Action: Pharmacotherapy NCIT:C15986

Agent: ataluren ↗

Ataluren plus standard care promotes readthrough of premature stop codons for ambulatory patients with nonsense mutation DMD, delaying functional and respiratory disease-progression milestones.

Show evidence (1 reference)

DOI:10.1007/s00415-023-11687-1 SUPPORT Human Clinical

"Kaplan–Meier analyses demonstrated that ataluren plus SoC significantly delayed age at loss of ambulation by 4 years (p < 0.0001) and age at decline to %-predicted forced vital capacity of < 60% and < 50% by 1.8 years (p = 0.0021) and 2.3 years (p = 0.0207), respectively, compared with SoC alone."

The STRIDE registry compared ataluren plus standard care with CINRG natural-history standard care and showed delayed loss of ambulation and respiratory decline milestones in nonsense-mutation DMD.

Gene Therapy

Action: gene therapy MAXO:0001001

Micro-dystrophin gene delivery via AAV vectors in clinical trials.

Sevasemten (EDG-5506)

Action: fast skeletal muscle myosin allosteric inhibitor Ontology label: Pharmacotherapy NCIT:C15986

Selective, orally active allosteric inhibitor of fast skeletal muscle myosin (Edgewise Therapeutics; investigational). Modest reduction of fast-fiber contraction is sufficient to protect dystrophin-deficient muscle from contraction-induced membrane injury without compromising overall strength or coordination.

Mechanism Target:

INHIBITS Sarcolemmal Fragility — Modulating fast skeletal muscle contraction reduces the mechanical stress experienced by the dystrophin-deficient sarcolemma, protecting fragile fast fibers from contraction-induced membrane injury.

Show evidence (1 reference)

PMID:36995778 SUPPORT Model Organism

"even modest decreases of contraction (<15%) were sufficient to protect skeletal muscles in dystrophic mdx mice from stress injury"

Demonstrates that reducing fast-fiber contraction with EDG-5506 protects dystrophic muscle from mechanical-stress-induced injury, the proximate consequence of sarcolemmal fragility.

Show evidence (4 references)

PMID:36995778 SUPPORT Model Organism

"We explored the role of fast skeletal muscle contraction in DMD with a potentially novel, selective, orally active inhibitor of fast skeletal muscle myosin, EDG-5506."

Identifies EDG-5506 (sevasemten) as a selective, orally active inhibitor of fast skeletal muscle myosin used to interrogate contraction's contribution to DMD pathophysiology.

PMID:36995778 SUPPORT Model Organism

"Longer-term treatment also decreased muscle fibrosis in key disease-implicated tissues."

Sustained fast-myosin inhibition reduces downstream fibrotic remodeling in dystrophic skeletal muscle, supporting a disease-modifying effect beyond acute membrane protection.

PMID:36995778 SUPPORT Model Organism

"in dystrophic dogs, EDG-5506 reversibly reduced circulating muscle injury biomarkers and increased habitual activity."

Cross-species replication in the GRMD dog model shows reduction of circulating muscle injury biomarkers and increased habitual activity with EDG-5506 treatment.

+ 1 more reference

Agents/Circumstances to Avoid

Action: supportive care MAXO:0000950

Botulinum toxin injections are contraindicated. Succinylcholine and inhalational anesthetics should be avoided due to susceptibility to malignant hyperthermia or malignant hyperthermia-like reactions.

Show evidence (1 reference)

PMID:20301298 SUPPORT Human Clinical

"Agents/circumstances to avoid: Botulinum toxin injections; succinylcholine and inhalational anesthetics because of susceptibility to malignant hyperthermia or malignant hyperthermia-like reactions."

GeneReviews explicitly lists botulinum toxin, succinylcholine, and inhalational anesthetics as agents/circumstances to avoid in dystrophinopathies due to malignant hyperthermia susceptibility.

🔬

Biochemical Markers

5

Creatine Kinase (Elevated)

Context: Markedly elevated (10-100x normal), highest in early disease

Pathograph Readouts

Readout Of Sarcolemmal Fragility Positive Diagnostic

Elevated serum CK reflects leakage from damaged skeletal muscle fibers and is a biochemical readout of sarcolemmal injury in DMD.

Show evidence (1 reference)

PMID:3302699 SUPPORT Human Clinical

"Serum levels of creatine kinase (CK) isoenzymes (MM, MB, and BB) were measured by sensitive enzyme immunoassay (EIA) methods in 50 patients with Duchenne muscular dystrophy (DMD) and in 39 controls. MM, MB, and BB levels in DMD patients were higher than in controls, and these three levels..."

This patient-control enzyme-immunoassay study supports elevated serum CK isoenzymes as a biochemical marker of Duchenne muscular dystrophy.

Dystrophin (Absent)

Context: Absent or severely reduced on muscle biopsy immunostaining

Pathograph Readouts

Readout Of Dystrophin Deficiency Present Absent Diagnostic

Absent or severely reduced dystrophin staining directly reports the proximal dystrophin-deficiency mechanism.

Show evidence (1 reference)

PMID:2674948 SUPPORT Human Clinical

"There was a very strong correlation of clinical diagnoses with the type of dystrophin abnormality; all Duchenne muscular dystrophy patient muscle contained no detectable dystrophin, Becker muscular dystrophy patient muscle had clearly abnormal dystrophin, and unrelated diseases showed normal dystrophin."

Immunoblot and immunofluorescence testing in human muscle directly supports absent dystrophin as a Duchenne biochemical diagnostic marker.

Treatment-Induced Dystrophin Expression (Treatment-induced)

Context: Measured in skeletal muscle biopsy after exon-skipping antisense oligonucleotide therapy; distinct from baseline diagnostic absence of dystrophin.

Pathograph Readouts

Pharmacodynamic Marker Of Dystrophin Deficiency Present Absent Pharmacodynamic

Treatment-induced dystrophin expression in skeletal muscle reports pharmacodynamic correction at the dystrophin-deficiency node for exon-skipping therapies.

FDA-SE-adult-noncancer-022 FDA

Skeletal muscle dystrophin

Accelerated Reasonably Likely Surrogate Endpoint

Patients with DMD who have a confirmed mutation of the DMD gene that is amenable to exon skipping

FDA-SE-pediatric-noncancer-017 FDA

Skeletal muscle dystrophin

Accelerated Reasonably Likely Surrogate Endpoint

Patients with DMD who have a confirmed mutation of the DMD gene that is amenable to exon skipping

Show evidence (1 reference)

PMID:29752304 SUPPORT Human Clinical

"Taken together, the 4 assays, each based on unique evaluation mechanisms, provided evidence of eteplirsen muscle cell penetration, exon skipping, and induction of novel dystrophin expression."

This eteplirsen study supports treatment-induced dystrophin expression as a measured pharmacodynamic biomarker for exon-skipping therapy in DMD.

Micro-dystrophin Expression (Treatment-induced)

Context: Measured in muscle biopsy after delandistrogene moxeparvovec gene therapy; distinguish from endogenous full-length dystrophin.

Pathograph Readouts

Pharmacodynamic Marker Of Dystrophin Deficiency Present Absent Pharmacodynamic

Treatment-induced micro-dystrophin expression reports biological response at the dystrophin-deficiency node rather than baseline disease status.

Show evidence (1 reference)

PMID:37539981 SUPPORT Human Clinical

"The primary endpoint was change from baseline (CFBL) to week 12 in delandistrogene moxeparvovec micro-dystrophin by western blot. Additional endpoints evaluated included: safety; vector genome copies; CFBL to week 12 in muscle fiber-localized micro-dystrophin by immunofluorescence; and..."

The ENDEAVOR DMD gene-therapy study used micro-dystrophin expression in muscle biopsy as a measured biochemical endpoint.

N-terminal Titin Fragment (Treatment-responsive)

Context: Urinary N-terminal titin fragment measured by proteomic profiling; pharmacodynamic biomarker of microdystrophin gene-therapy efficacy. More sensitive than serum CK at low levels of expressed microdystrophin.

Pathograph Readouts

Pharmacodynamic Marker Of Sarcolemmal Fragility Negative Pharmacodynamic

Reduction in urinary N-terminal titin fragment levels reports pharmacodynamic correction of myofiber membrane injury after AAV microdystrophin restoration.

Show evidence (3 references)

PMID:38229112 SUPPORT Human Clinical

"Potential PD biomarkers in DMD participant urine were examined using a proteomic approach on the Somalogic platform."

Identifies urinary N-terminal titin fragment as a candidate pharmacodynamic biomarker in human DMD participants via Somalogic proteomic profiling.

PMID:38229112 SUPPORT Model Organism

"Findings were confirmed in both mdx mice and Golden Retriever muscular dystrophy (GRMD) dog plasma samples."

mdx mouse and GRMD dog plasma data confirm cross-species reproducibility of titin fragment changes as a DMD biomarker.

PMID:38229112 SUPPORT Human Clinical

"The measurement of objective PD biomarkers such as titin may provide additional confidence in the assessment of the mechanism of action and efficacy in gene therapy clinical trials of DMD."

Author conclusion positions titin as a pharmacodynamic biomarker to complement functional outcome measures in DMD gene therapy trials.

🔬

Clinical Trials

1

NCT05540860 PHASE_II ACTIVE_NOT_RECRUITING

LYNX — 2-part, multicenter, Phase 2 study of safety, pharmacokinetics and biomarkers of sevasemten (EDG-5506) in children with Duchenne muscular dystrophy. Randomized, double-blind, placebo-controlled Part A followed by an open-label Part B.

Show evidence (1 reference)

clinicaltrials:NCT05540860 SUPPORT

"The LYNX study is a 2-part, multicenter, Phase 2 study of safety, pharmacokinetics and biomarkers in children with Duchenne muscular dystrophy including a randomized, double-blind, placebo-controlled part A, followed by an open-label part B."

ClinicalTrials.gov record for the pediatric DMD Phase 2 trial of sevasemten (EDG-5506) — the clinical translation of the preclinical mechanism reported in PMID:36995778.

{ }

Source YAML

click to show

name: Duchenne Muscular Dystrophy
creation_date: '2026-01-07T17:31:51Z'
updated_date: '2026-05-21T04:04:17Z'
category: Genetic
parents:
- Muscular Dystrophy
- Neuromuscular Disease
disease_term:
  preferred_term: Duchenne muscular dystrophy
  term:
    id: MONDO:0010679
    label: Duchenne muscular dystrophy
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0010679
      label: Duchenne muscular dystrophy
    mapping_predicate: skos:exactMatch
    mapping_source: ORPHA:98896
    mapping_justification: >-
      Orphanet's cross-reference table lists "MONDO:0010679 | Exact" for the
      Duchenne muscular dystrophy record.
external_assertions:
- name: Orphanet Duchenne muscular dystrophy record
  source: Orphanet
  assertion_type: structured_disease_record
  external_id: ORPHA:98896
  url: http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=98896
  description: >-
    Orphanet curates ORPHA:98896 as the Duchenne muscular dystrophy disorder
    record and links it to exact MONDO and OMIM cross-references, plus ICD,
    Genetic and Rare Diseases Information Center, MeSH, MedDRA, and UMLS
    cross-references.
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "ORPHA:98896  Duchenne muscular dystrophy"
    explanation: >-
      The Orphanet structured record heading identifies ORPHA:98896 as the
      Duchenne muscular dystrophy disease record.
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "MONDO:0010679 | Exact"
    explanation: >-
      Orphanet maps ORPHA:98896 exactly to the same MONDO disease identifier
      used as this entry's disease term.
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "OMIM:310200 | Exact"
    explanation: >-
      Orphanet also lists OMIM:310200 as an exact cross-reference for the DMD
      disorder record.
inheritance:
- name: X-linked recessive inheritance
  inheritance_term:
    preferred_term: X-linked recessive inheritance
    term:
      id: HP:0001419
      label: X-linked recessive inheritance
  description: >-
    Orphanet classifies Duchenne muscular dystrophy as an X-linked recessive
    disorder.
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "X-linked recessive"
    explanation: >-
      The Orphanet inheritance section directly states the X-linked recessive
      mode of inheritance for Duchenne muscular dystrophy.
progression:
- phase: Clinical onset
  age_range: Childhood
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Age of onset: Childhood"
    explanation: >-
      Orphanet's natural-history field classifies Duchenne muscular dystrophy
      onset as childhood onset.
has_subtypes:
- name: Classic Duchenne
  description: Complete absence of dystrophin, onset by age 5, wheelchair-dependent by early teens.
- name: Intermediate DMD
  description: Partial dystrophin expression, intermediate severity between DMD and Becker.
prevalence:
- population: Global male population
  percentage: 7.1 per 100,000 males
  notes: >-
    A 2020 systematic review and meta-analysis estimated the pooled global DMD
    prevalence at 7.1 per 100,000 males.
  evidence:
  - reference: PMID:32503598
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The pooled global DMD prevalence was 7.1 cases (95% CI: 5.0-10.1) per
      100,000 males and 2.8 cases (95% CI: 1.6-4.6) per 100,000 in the general
      population, while the pooled global DMD birth prevalence was 19.8 (95%
      CI:16.6-23.6) per 100,000 live male births.
    explanation: >-
      This systematic review/meta-analysis provides the strongest pooled global
      prevalence estimate for DMD in males.
- population: Global live male births
  percentage: 19.8 per 100,000 live male births
  notes: >-
    The same meta-analysis estimated the pooled global DMD birth prevalence at
    19.8 per 100,000 live male births.
  evidence:
  - reference: PMID:32503598
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The pooled global DMD prevalence was 7.1 cases (95% CI: 5.0-10.1) per
      100,000 males and 2.8 cases (95% CI: 1.6-4.6) per 100,000 in the general
      population, while the pooled global DMD birth prevalence was 19.8 (95%
      CI:16.6-23.6) per 100,000 live male births.
    explanation: >-
      The same meta-analysis also supplies the pooled global live-birth
      prevalence estimate for DMD.
- population: Worldwide population
  percentage: 1-9 per 100,000
  notes: >-
    Orphanet classifies the worldwide DMD point-prevalence band as 1-9 per
    100,000.
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "1-9 / 100 000 | Worldwide | Point prevalence | PMID:32503598"
    explanation: >-
      Orphanet's epidemiology table provides a worldwide point-prevalence range
      for Duchenne muscular dystrophy.
- population: Worldwide live births
  percentage: 1-9 per 100,000 live births
  notes: >-
    Orphanet classifies the worldwide DMD birth-prevalence band as 1-9 per
    100,000 live births.
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "1-9 / 100 000 | Worldwide | Prevalence at birth | PMID:32503598"
    explanation: >-
      Orphanet's epidemiology table provides a worldwide prevalence-at-birth
      range for Duchenne muscular dystrophy.
mechanistic_hypotheses:
- hypothesis_group_id: canonical_dystrophin_loss_membrane_fragility_model
  hypothesis_label: Canonical Dystrophin Loss and Membrane Fragility Model
  status: CANONICAL
  description: >-
    Out-of-frame DMD variants abolish functional dystrophin, the cytoskeletal link between cytoplasmic F-actin and the sarcolemmal dystrophin-glycoprotein complex (DGC). Without dystrophin the DGC is destabilized at the sarcolemma, leaving muscle fibers vulnerable to contraction-induced mechanical injury, calcium influx through stretched/damaged membrane, and activation of calcium-dependent proteases. Repeated cycles of fiber necrosis, satellite-cell-driven regeneration, chronic inflammation, and progressive fibro-fatty replacement of muscle ultimately exhaust regenerative capacity, producing the characteristic progressive proximal weakness, cardiomyopathy, respiratory failure, and short life expectancy of Duchenne muscular dystrophy. Exon-skipping and gene-replacement therapies that restore even partial dystrophin expression provide interventional validation of this canonical chain.
  evidence:
  - reference: PMID:16770791
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The severe Duchenne and milder Becker muscular dystrophy are both caused by mutations"
    explanation: >
      Canonical mechanism review used as the seed reference for the
      hypothesis-search deep-research run.
pathophysiology:
- name: DMD Loss-of-Function Variants
  description: >-
    Duchenne muscular dystrophy is caused by pathogenic variants in the X-linked
    DMD gene that abolish or severely reduce functional dystrophin. Out-of-frame
    deletions, duplications, nonsense, frameshift, and splice-disrupting variants
    typically produce the Duchenne phenotype, whereas in-frame variants that
    preserve partially functional dystrophin more often produce Becker or
    intermediate dystrophinopathy.
  gene:
    preferred_term: DMD
    modifier: DECREASED
    term:
      id: hgnc:2928
      label: DMD
  evidence:
  - reference: PMID:23650001
    reference_title: "Two mutations in one dystrophin gene."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Duchenne/Becker muscular dystrophies (DMD/BMD) lead to progressive
      irreversible muscle deterioration caused by recessive mutations in the
      dystrophin encoding gene (Xp21.1). Approximately 60% of mutations are
      deletions, 10% are duplications and the remaining 30% are point mutations.
    explanation: >-
      This human molecular cohort summary supports DMD as the causal gene and
      gives the major mutation classes that initiate the dystrophinopathy path.
  - reference: PMID:16770791
    reference_title: "Entries in the Leiden Duchenne muscular dystrophy mutation database: an overview of mutation types and paradoxical cases that confirm the reading-frame rule."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The severe Duchenne and milder Becker muscular dystrophy are both caused
      by mutations in the DMD gene. This gene codes for dystrophin, a protein
      important for maintaining the stability of muscle-fiber membranes.
    explanation: >-
      The Leiden mutation database review links DMD variants to dystrophin and
      membrane-stability phenotypes across Duchenne and Becker dystrophinopathy.
  downstream:
  - target: Dystrophin Deficiency
    description: >-
      Duchenne-associated DMD variants disrupt the reading frame or truncate the
      transcript, leaving little or no functional dystrophin in striated muscle.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:16770791
      reference_title: "Entries in the Leiden Duchenne muscular dystrophy mutation database: an overview of mutation types and paradoxical cases that confirm the reading-frame rule."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In Duchenne patients, mutations induce a shift in the reading frame
        leading to prematurely truncated, dysfunctional dystrophins.
      explanation: >-
        This directly supports the edge from Duchenne-type DMD mutations to
        absent or severely dysfunctional dystrophin.
- name: Dystrophin Deficiency
  description: >-
    Mutations in the DMD gene cause absent or dysfunctional dystrophin protein.
    Dystrophin links the cytoskeleton to the extracellular matrix in muscle
    fibers and cardiomyocytes, providing structural stability during contraction.
  gene:
    preferred_term: DMD
    modifier: DECREASED
    term:
      id: hgnc:2928
      label: DMD
  cell_types:
  - preferred_term: Skeletal Muscle Fiber
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  - preferred_term: Cardiac Muscle Cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  biological_processes:
  - preferred_term: Plasma Membrane Organization
    modifier: DECREASED
    term:
      id: GO:0007009
      label: plasma membrane organization
  evidence:
  - reference: PMID:37435300
    reference_title: "Duchenne muscular dystrophy: disease mechanism and therapeutic strategies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The identification of the dystrophin gene as central to DMD pathogenesis has led to the understanding of the muscle membrane and the proteins involved in membrane stability as the focal point of the disease."
    explanation: Review confirms dystrophin gene mutations cause membrane instability as the central pathogenic mechanism.
  - reference: PMID:23620650
    reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The genetic cause of DMD is an x-chromosomal mutation of the dystrophin
      gene. Dystrophin mechanically stabilises myofibres by linking the
      cytoskeleton to the basal lamina through the dystroglycan complex.
    explanation: >-
      This mechanistic review ties the causal DMD mutation to loss of the
      dystrophin mechanical-stability function in myofibres.
  downstream:
  - target: Dystrophin-Glycoprotein Complex Destabilization
    description: >-
      Loss of dystrophin disconnects cytoskeletal and membrane elements,
      destabilizing the dystrophin-glycoprotein complex at the sarcolemma.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:15117830
      reference_title: "The dystrophin glycoprotein complex: signaling strength and integrity for the sarcolemma."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Dystrophin, the protein product of the Duchenne and X-linked dilated
        cardiomyopathy locus, links cytoskeletal and membrane elements.
      explanation: >-
        Dystrophin is the direct cytoskeletal-membrane linker, so its absence
        directly destabilizes the complex it anchors.
- name: Dystrophin-Glycoprotein Complex Destabilization
  description: >-
    The dystrophin-glycoprotein complex normally stabilizes cardiac and skeletal
    muscle sarcolemma by coupling the cytoskeleton, plasma membrane, and
    extracellular matrix. Dystrophin loss destabilizes this complex and leaves
    striated muscle cells vulnerable to contraction-associated membrane damage.
  cell_types:
  - preferred_term: Skeletal Muscle Fiber
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  - preferred_term: Cardiac Muscle Cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  biological_processes:
  - preferred_term: Plasma Membrane Organization
    modifier: DECREASED
    term:
      id: GO:0007009
      label: plasma membrane organization
  evidence:
  - reference: PMID:15117830
    reference_title: "The dystrophin glycoprotein complex: signaling strength and integrity for the sarcolemma."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      The dystrophin glycoprotein complex (DGC) is a specialization of cardiac
      and skeletal muscle membrane. This large multicomponent complex has both
      mechanical stabilizing and signaling roles in mediating interactions
      between the cytoskeleton, membrane, and extracellular matrix.
    explanation: >-
      This defines the DGC as the mechanical and signaling scaffold disrupted
      downstream of dystrophin deficiency.
  downstream:
  - target: Sarcolemmal Fragility
    description: >-
      DGC destabilization causes fragile, leaky striated-muscle membranes during
      contraction.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:15117830
      reference_title: "The dystrophin glycoprotein complex: signaling strength and integrity for the sarcolemma."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Animal models of DGC mutants have shown that destabilization of the DGC
        leads to membrane fragility and loss of membrane integrity, resulting in
        degeneration of skeletal muscle and cardiomyocytes.
      explanation: >-
        This directly supports membrane fragility downstream of DGC
        destabilization in skeletal muscle and cardiomyocytes.
  - target: Cardiac Myocyte Injury
    description: >-
      The same DGC fragility mechanism injures dystrophin-deficient
      cardiomyocytes and contributes to progressive cardiac remodeling.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:15117830
      reference_title: "The dystrophin glycoprotein complex: signaling strength and integrity for the sarcolemma."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Animal models of DGC mutants have shown that destabilization of the DGC
        leads to membrane fragility and loss of membrane integrity, resulting in
        degeneration of skeletal muscle and cardiomyocytes.
      explanation: >-
        The cited DGC mutant models explicitly include cardiomyocyte degeneration
        as a consequence of DGC destabilization.
- name: Sarcolemmal Fragility
  description: >-
    Unprotected sarcolemma undergoes contraction-induced microtears and loss of
    membrane integrity, releasing intracellular enzymes and creating the entry
    point for downstream calcium injury.
  cell_types:
  - preferred_term: Skeletal Muscle Fiber
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  - preferred_term: Cardiac Muscle Cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  biological_processes:
  - preferred_term: Plasma Membrane Organization
    modifier: DECREASED
    term:
      id: GO:0007009
      label: plasma membrane organization
  evidence:
  - reference: PMID:15117830
    reference_title: "The dystrophin glycoprotein complex: signaling strength and integrity for the sarcolemma."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Animal models of DGC mutants have shown that destabilization of the DGC
      leads to membrane fragility and loss of membrane integrity, resulting in
      degeneration of skeletal muscle and cardiomyocytes.
    explanation: >-
      This directly supports sarcolemmal fragility downstream of DGC
      destabilization.
  downstream:
  - target: Calcium Influx
    description: >-
      Loss of sarcolemmal integrity permits pathologic calcium entry into
      dystrophin-deficient muscle cells.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:1497954
      reference_title: "Pathogenesis of Duchenne muscular dystrophy: the calcium hypothesis revisited."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Partial failure of the pump would result in intracellular accumulation
        of calcium, hypercontractions of the sarcomeres, rupture of the cell
        membrane, massive influx of calcium and cell necrosis.
      explanation: >-
        The calcium-hypothesis review links membrane rupture to massive calcium
        influx in DMD pathogenesis.
  - target: TRPC/SOCE-mediated Calcium Entry
    description: >-
      Membrane instability activates TRPC channels and STIM1/ORAI1
      store-operated calcium entry as a parallel route of pathologic calcium
      entry into dystrophic myofibers.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:19864620
      reference_title: "Calcium influx is sufficient to induce muscular dystrophy through a TRPC-dependent mechanism."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        TRPC channels are key disease initiators downstream of the unstable
        membrane that characterizes many types of muscular dystrophy.
      explanation: >-
        The Millay et al. study identifies TRPC channels as disease initiators
        operating downstream of the unstable dystrophic sarcolemma.
  - target: Elevated Creatine Kinase
    description: Membrane leak and myofiber injury release CK into serum.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34626608
      reference_title: "Creatine kinase test diagnostic accuracy in neonatal screening for Duchenne Muscular Dystrophy: A systematic review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        the creatine kinase test showed good accuracy in screening for cases of
        Duchenne Muscular Dystrophy and may be a useful alternative in the early
        diagnosis of the disease followed by confirmatory genetic testing.
      explanation: >-
        Serum CK is a clinically validated readout of membrane leak and muscle
        injury in the DMD diagnostic path.
- name: Calcium Influx
  description: >-
    Calcium enters dystrophin-deficient muscle cells through damaged membrane,
    contributing to hypercontraction, protease activation, and downstream
    myofiber necrosis.
  cell_types:
  - preferred_term: Skeletal Muscle Fiber
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  - preferred_term: Cardiac Muscle Cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  biological_processes:
  - preferred_term: Calcium Ion Transport Into Cytosol
    modifier: INCREASED
    term:
      id: GO:0060402
      label: calcium ion transport into cytosol
  evidence:
  - reference: PMID:1497954
    reference_title: "Pathogenesis of Duchenne muscular dystrophy: the calcium hypothesis revisited."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Partial failure of the pump would result in intracellular accumulation of
      calcium, hypercontractions of the sarcomeres, rupture of the cell
      membrane, massive influx of calcium and cell necrosis.
    explanation: >-
      This classic calcium-hypothesis review links calcium accumulation,
      membrane rupture, calcium influx, and necrosis in DMD pathogenesis.
  downstream:
  - target: Myofiber Necrosis
    description: >-
      Calcium overload, membrane rupture, and contraction injury drive myofiber
      necrosis.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:1497954
      reference_title: "Pathogenesis of Duchenne muscular dystrophy: the calcium hypothesis revisited."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Partial failure of the pump would result in intracellular accumulation of
        calcium, hypercontractions of the sarcomeres, rupture of the cell
        membrane, massive influx of calcium and cell necrosis.
      explanation: >-
        The calcium hypothesis provides direct mechanistic support for necrosis
        downstream of sarcolemmal rupture and calcium influx.
- name: TRPC/SOCE-mediated Calcium Entry
  description: >-
    A parallel pathologic calcium entry route in dystrophic muscle operating
    through transient receptor potential canonical (TRPC) cation channels and
    STIM1-ORAI1 store-operated calcium entry (SOCE) complexes. Genetic studies
    in mice show that activation of these channels alone is sufficient to
    recapitulate the dystrophic phenotype, and that inhibiting them ameliorates
    pathology in mdx and delta-sarcoglycan-deficient models. This mechanism
    operates downstream of the unstable sarcolemma but independently of direct
    membrane rupture as a route of calcium influx.
  cell_types:
  - preferred_term: Skeletal Muscle Fiber
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  - preferred_term: Cardiac Muscle Cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  biological_processes:
  - preferred_term: Store-Operated Calcium Entry
    modifier: INCREASED
    term:
      id: GO:0002115
      label: store-operated calcium entry
  - preferred_term: Calcium Ion Transmembrane Transport
    modifier: INCREASED
    term:
      id: GO:0070588
      label: calcium ion transmembrane transport
  evidence:
  - reference: PMID:19864620
    reference_title: "Calcium influx is sufficient to induce muscular dystrophy through a TRPC-dependent mechanism."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      overexpression of transient receptor potential canonical 3 (TRPC3) and
      the associated increase in calcium influx resulted in a phenotype of
      muscular dystrophy nearly identical to that observed in DGC-lacking
      dystrophic disease models
    explanation: >-
      TRPC3 overexpression alone induces a dystrophic phenotype indistinguishable
      from genetic DGC loss, demonstrating TRPC-mediated calcium entry is
      sufficient to drive muscular dystrophy in vivo.
  - reference: PMID:19864620
    reference_title: "Calcium influx is sufficient to induce muscular dystrophy through a TRPC-dependent mechanism."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      transgene-mediated inhibition of TRPC channels in mice dramatically
      reduced calcium influx and dystrophic disease manifestations associated
      with the mdx mutation (dystrophin gene) and deletion of the
      delta-sarcoglycan (Scgd) gene.
    explanation: >-
      Conversely, TRPC channel inhibition rescues dystrophic disease in mdx
      mice, establishing TRPC-mediated calcium influx as causal in DMD-relevant
      models.
  - reference: PMID:26088163
    reference_title: "Genetic evidence in the mouse solidifies the calcium hypothesis of myofiber death in muscular dystrophy."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      models with artificially elevated calcium in skeletal muscle manifest
      fulminant dystrophic-like disease, whereas models with enhanced calcium
      clearance or inhibited calcium influx are resistant to myofiber death and
      MD.
    explanation: >-
      Reviews the genetic mouse evidence (including STIM1/ORAI1 and TRPC
      manipulations) that elevated cytosolic calcium alone is sufficient to
      drive dystrophic disease independent of membrane rupture.
  downstream:
  - target: Myofiber Necrosis
    description: >-
      Calcium overload via TRPC channels and STIM1-ORAI1 store-operated entry
      activates calcium-dependent proteases and mitochondrial permeability
      transition, driving myofiber necrosis independently of direct sarcolemmal
      rupture.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:26088163
      reference_title: "Genetic evidence in the mouse solidifies the calcium hypothesis of myofiber death in muscular dystrophy."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        models with artificially elevated calcium in skeletal muscle manifest
        fulminant dystrophic-like disease, whereas models with enhanced calcium
        clearance or inhibited calcium influx are resistant to myofiber death
        and MD.
      explanation: >-
        Genetic evidence that elevated cytosolic calcium in skeletal muscle is
        sufficient to drive the dystrophic-disease/myofiber-necrosis phenotype.
- name: Myofiber Necrosis
  description: >-
    Repeated contraction-associated membrane injury causes skeletal myofiber
    necrosis, releasing damage signals that initiate inflammatory remodeling and
    repeated repair attempts.
  cell_types:
  - preferred_term: Skeletal Muscle Fiber
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  evidence:
  - reference: PMID:23620650
    reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Finally, the cellular integrity is unsustainable. Myofibre necrosis and
      inflammation lead to fibrotic tissue remodelling.
    explanation: >-
      This supports myofiber necrosis as the immediate tissue-injury event that
      precedes inflammatory and fibrotic remodeling.
  downstream:
  - target: Failed Satellite Cell Regeneration
    description: >-
      Continuous myofiber breakdown exceeds the compensatory capacity of
      satellite-cell proliferation.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23620650
      reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In DMD, constant myofibre breakdown cannot be fully compensated for by
        satellite cell proliferation.
      explanation: >-
        This directly supports failed regenerative compensation downstream of
        recurrent myofiber breakdown.
  - target: Chronic Muscle Inflammation
    description: >-
      Necrotic muscle fibers trigger inflammatory mediators and immune-cell
      recruitment, sustaining a tissue-damage cycle.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23620650
      reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Finally, the cellular integrity is unsustainable. Myofibre necrosis and
        inflammation lead to fibrotic tissue remodelling.
      explanation: >-
        The review explicitly couples myofibre necrosis and inflammation as
        sequential contributors to downstream remodeling.
- name: Failed Satellite Cell Regeneration
  description: >-
    Satellite-cell proliferation attempts to repair ongoing dystrophic injury,
    but repeated necrosis outpaces regenerative capacity and leaves muscle loss
    progressively irreversible.
  cell_types:
  - preferred_term: Skeletal Muscle Satellite Stem Cell
    term:
      id: CL:0008011
      label: skeletal muscle satellite stem cell
  evidence:
  - reference: PMID:23620650
    reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In DMD, constant myofibre breakdown cannot be fully compensated for by
      satellite cell proliferation.
    explanation: >-
      This supports failed satellite-cell compensation as a distinct event in
      the mutation-to-phenotype path.
  downstream:
  - target: Progressive Muscle Degeneration
    description: >-
      Failed regenerative compensation allows irreversible loss of functional
      myofibers to accumulate over time.
    causal_link_type: DIRECT
- name: Chronic Muscle Inflammation
  description: >-
    Necrotic dystrophic muscle releases damage signals that recruit macrophages
    and amplify cytokine-mediated injury. Persistent inflammation links the
    primary membrane defect to fibrotic remodeling.
  cell_types:
  - preferred_term: Macrophage
    term:
      id: CL:0000235
      label: macrophage
  biological_processes:
  - preferred_term: Inflammatory Response
    modifier: INCREASED
    term:
      id: GO:0006954
      label: inflammatory response
  evidence:
  - reference: PMID:23620650
    reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Calcium acts as a second messenger and activates a cascade of inflammatory
      processes.
    explanation: >-
      This links calcium-overload injury to inflammatory signaling in the DMD
      causal path.
  downstream:
  - target: Fibrofatty Muscle Replacement
    description: >-
      Persistent inflammation after necrosis promotes extracellular-matrix
      remodeling, fibrosis, and fatty replacement of muscle.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23620650
      reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Inflammatory processes following muscular necrosis lead to fibrotic
        remodelling and finally fatty cell replacement.
      explanation: >-
        This directly supports inflammation as the bridge from necrosis to
        fibrotic and fatty replacement.
- name: Fibrofatty Muscle Replacement
  description: >-
    Chronic dystrophic injury activates fibroblasts and myofibroblast-like
    remodeling programs, depositing extracellular matrix and replacing functional
    muscle with fibrotic and fatty tissue. This tissue-level remodeling causes
    calf pseudohypertrophy and reduces contractile reserve.
  cell_types:
  - preferred_term: Fibroblast
    term:
      id: CL:0000057
      label: fibroblast
  - preferred_term: Adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  biological_processes:
  - preferred_term: Extracellular Matrix Organization
    modifier: INCREASED
    term:
      id: GO:0030198
      label: extracellular matrix organization
  evidence:
  - reference: PMID:23620650
    reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Inflammatory processes following muscular necrosis lead to fibrotic
      remodelling and finally fatty cell replacement.
    explanation: >-
      This supports fibrofatty replacement as the downstream tissue-remodeling
      consequence of repeated necrosis and inflammation.
  downstream:
  - target: Progressive Muscle Degeneration
    description: >-
      Fibrosis and fat replacement remove functional contractile fibers and
      make weakness progressively irreversible.
    causal_link_type: DIRECT
  - target: Pseudohypertrophy of Calves
    description: >-
      Preferential fibrofatty remodeling of posterior calf muscles enlarges the
      calves despite loss of contractile muscle.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23620650
      reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In DMD this phenomenon is often first seen in the posterior calf
        musculature, which is prone to overtraining because of its function as
        anti-gravity stabilizer (Fig. 1).
      explanation: >-
        The review places fibrofatty replacement early in the posterior calf
        musculature, explaining the calf pseudohypertrophy phenotype.
- name: Progressive Muscle Degeneration
  description: >-
    Without dystrophin, muscle fibers are susceptible to contraction-induced damage.
    Repeated cycles of degeneration and regeneration exhaust satellite cell pools,
    leading to fibrosis and fatty replacement of muscle tissue.
  cell_types:
  - preferred_term: Skeletal Muscle Fiber
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  biological_processes:
  - preferred_term: Skeletal Muscle Contraction
    modifier: DECREASED
    term:
      id: GO:0003009
      label: skeletal muscle contraction
  evidence:
  - reference: PMID:37435300
    reference_title: "Duchenne muscular dystrophy: disease mechanism and therapeutic strategies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."
    explanation: Review confirms progressive muscle wasting is a defining feature of DMD.
  downstream:
  - target: Progressive Muscle Weakness
    description: Loss of contractile fibers causes steadily worsening proximal weakness.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:37435300
      reference_title: "Duchenne muscular dystrophy: disease mechanism and therapeutic strategies."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."
      explanation: >-
        Progressive skeletal muscle wasting directly explains the progressive
        weakness phenotype.
  - target: Gowers Sign
    description: Hip and thigh extensor weakness produces compensatory Gowers maneuver.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Proximal hip and thigh weakness impairs rising from the floor.
  - target: Respiratory Muscle Weakness
    description: >-
      The same progressive degeneration affects diaphragm and intercostal
      muscles, reducing ventilatory reserve and cough strength.
    causal_link_type: DIRECT
- name: Respiratory Muscle Weakness
  description: >-
    Progressive dystrophic degeneration of diaphragm and intercostal skeletal
    muscle reduces ventilation, cough effectiveness, and airway clearance,
    creating the respiratory-insufficiency branch of DMD.
  cell_types:
  - preferred_term: Skeletal Muscle Fiber
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  biological_processes:
  - preferred_term: Skeletal Muscle Contraction
    modifier: DECREASED
    term:
      id: GO:0003009
      label: skeletal muscle contraction
  evidence:
  - reference: PMID:37435300
    reference_title: "Duchenne muscular dystrophy: disease mechanism and therapeutic strategies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."
    explanation: >-
      The review identifies respiratory insufficiency as part of the progressive
      skeletal-muscle wasting phenotype.
  downstream:
  - target: Respiratory Insufficiency
    description: Diaphragmatic and intercostal weakness reduce ventilation and cough effectiveness.
    causal_link_type: DIRECT
- name: Cardiac Myocyte Injury
  description: >-
    Dystrophin deficiency in cardiomyocytes destabilizes the DGC, exposing the
    myocardium to membrane injury, calcium stress, and myocyte degeneration.
  cell_types:
  - preferred_term: Cardiac Muscle Cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  biological_processes:
  - preferred_term: Cardiac Muscle Contraction
    modifier: DECREASED
    term:
      id: GO:0060048
      label: cardiac muscle contraction
  evidence:
  - reference: PMID:15117830
    reference_title: "The dystrophin glycoprotein complex: signaling strength and integrity for the sarcolemma."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Animal models of DGC mutants have shown that destabilization of the DGC
      leads to membrane fragility and loss of membrane integrity, resulting in
      degeneration of skeletal muscle and cardiomyocytes.
    explanation: >-
      This supports cardiomyocyte injury as a direct consequence of DGC
      destabilization.
  - reference: PMID:23620650
    reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mortality in DMD patients is often due to respiratory or cardiac problems."
    explanation: >-
      This supports cardiac involvement as a life-limiting downstream branch of
      DMD tissue injury.
  downstream:
  - target: Myocardial Fibrosis
    description: Injured dystrophin-deficient myocardium undergoes fibrotic remodeling.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23620650
      reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Mortality in DMD patients is often due to respiratory or cardiac
        problems. In both body areas – the pulmonary and the pericardial
        connective tissues – the fibrotic changes in muscular dystrophy tend to
        be very severely expressed and they tend to influence strongly muscular
        function (74, 75).
      explanation: >-
        The fibrosis review identifies severe fibrotic remodeling in the
        pericardial connective tissues as a cardiac branch of DMD pathology.
- name: Myocardial Fibrosis
  description: >-
    Recurrent cardiomyocyte injury and connective-tissue remodeling produce
    myocardial fibrosis, stiffening the myocardium and contributing to DMD
    cardiomyopathy.
  cell_types:
  - preferred_term: Cardiac Muscle Cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  - preferred_term: Fibroblast
    term:
      id: CL:0000057
      label: fibroblast
  biological_processes:
  - preferred_term: Extracellular Matrix Organization
    modifier: INCREASED
    term:
      id: GO:0030198
      label: extracellular matrix organization
  evidence:
  - reference: PMID:23620650
    reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Mortality in DMD patients is often due to respiratory or cardiac
      problems. In both body areas – the pulmonary and the pericardial
      connective tissues – the fibrotic changes in muscular dystrophy tend to be
      very severely expressed and they tend to influence strongly muscular
      function (74, 75).
    explanation: >-
      This supports myocardial and pericardial fibrosis as the downstream
      remodeling event that contributes to DMD cardiac disease.
  downstream:
  - target: Cardiomyopathy
    description: Progressive myocardial fibrosis and dysfunction produce dilated cardiomyopathy.
    causal_link_type: DIRECT
phenotypes:
- name: Progressive Muscle Weakness
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  diagnostic: true
  notes: Proximal muscles affected first, onset typically 2-5 years
  phenotype_term:
    preferred_term: Progressive Muscle Weakness
    term:
      id: HP:0003323
      label: Progressive muscle weakness
  evidence:
  - reference: PMID:37435300
    reference_title: "Duchenne muscular dystrophy: disease mechanism and therapeutic strategies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."
    explanation: Review confirms progressive skeletal muscle wasting as a defining feature of DMD.
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0003323 | Progressive muscle weakness | Very frequent (99-80%)"
    explanation: >-
      Orphanet's curated HPO annotation independently supports progressive
      muscle weakness as a very frequent DMD phenotype.
- name: Loss of ambulation
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  notes: Major functional milestone in DMD progression; glucocorticoid treatment delays loss of walking ability.
  phenotype_term:
    preferred_term: Loss of ambulation
    term:
      id: HP:0002505
      label: Loss of ambulation
  evidence:
  - reference: DOI:10.1186/s13023-024-03217-7
    reference_title: "Comprehensive analysis of 2097 patients with dystrophinopathy based on a database from 2011 to 2021"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The median age at loss of ambulation was 2.5 years later in DMD patients who received glucocorticoid treatment."
    explanation: Large dystrophinopathy cohort reports loss of ambulation as a treatment-sensitive DMD progression milestone.
- name: Gowers Sign
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  diagnostic: true
  notes: Using hands to push up from floor due to proximal weakness
  phenotype_term:
    preferred_term: Gowers Sign
    term:
      id: HP:0003391
      label: Gowers sign
  evidence:
  - reference: PMID:15106215
    reference_title: "Glucocorticoid corticosteroids for Duchenne muscular dystrophy."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "Improvements were seen in time taken to rise from the floor (Gowers' time), nine metres walking time, four-stair climbing time, ability to lift weights, leg function grade and forced vital capacity."
    explanation: Cochrane review uses Gowers time as an outcome measure, confirming its clinical relevance in DMD.
- name: Pseudohypertrophy of Calves
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  notes: Fatty and fibrous tissue replacement gives appearance of enlarged calves
  phenotype_term:
    preferred_term: Calf Pseudohypertrophy
    term:
      id: HP:0003707
      label: Calf muscle pseudohypertrophy
  evidence:
  - reference: PMID:23620650
    reference_title: "The role of fibrosis in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In DMD this phenomenon is often first seen in the posterior calf
      musculature, which is prone to overtraining because of its function as
      anti-gravity stabilizer (Fig. 1).
    explanation: >-
      The fibrosis review directly supports posterior calf involvement as an
      early fibrofatty remodeling site in DMD.
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: PARTIAL
    evidence_source: OTHER
    snippet: "HP:0008981 | Calf muscle hypertrophy | Very frequent (99-80%)"
    explanation: >-
      Orphanet records very frequent calf enlargement using HP:0008981. This
      supports the calf-enlargement phenotype, while this entry keeps the more
      precise DMD pseudohypertrophy term because the modeled mechanism is
      fibrofatty replacement rather than true muscle hypertrophy.
- name: Elevated Creatine Kinase
  category: Laboratory
  frequency: VERY_FREQUENT
  diagnostic: true
  notes: Often 10-100x normal, detectable from birth
  phenotype_term:
    preferred_term: Elevated Creatine Kinase
    term:
      id: HP:0003236
      label: Elevated circulating creatine kinase concentration
  evidence:
  - reference: PMID:34626608
    reference_title: "Creatine kinase test diagnostic accuracy in neonatal screening for Duchenne Muscular Dystrophy: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "the creatine kinase test showed good accuracy in screening for cases of Duchenne Muscular Dystrophy and may be a useful alternative in the early diagnosis of the disease followed by confirmatory genetic testing."
    explanation: Systematic review confirms CK testing has good diagnostic accuracy for DMD screening.
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0003236 | Elevated circulating creatine kinase concentration | Very frequent (99-80%)"
    explanation: >-
      Orphanet classifies elevated circulating creatine kinase as a very
      frequent DMD phenotype.
- name: Cardiomyopathy
  category: Cardiovascular
  frequency: VERY_FREQUENT
  notes: Dilated cardiomyopathy develops in nearly all patients by late teens
  phenotype_term:
    preferred_term: Dilated Cardiomyopathy
    term:
      id: HP:0001644
      label: Dilated cardiomyopathy
  evidence:
  - reference: PMID:37435300
    reference_title: "Duchenne muscular dystrophy: disease mechanism and therapeutic strategies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."
    explanation: Review confirms cardiomyopathy as a defining feature of DMD.
  - reference: PMID:22463839
    reference_title: "Effects of angiotensin-converting enzyme inhibitors and/or beta blockers on the cardiomyopathy in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cardiomyopathy is a consequence of Duchenne muscular dystrophy (DMD)."
    explanation: Study confirms cardiomyopathy as a consequence of DMD.
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001638 | Cardiomyopathy | Very frequent (99-80%)"
    explanation: >-
      Orphanet's HPO annotation supports cardiomyopathy as a very frequent
      phenotype in DMD; the existing phenotype term captures the common dilated
      cardiomyopathy presentation more specifically.
- name: Respiratory Insufficiency
  category: Respiratory
  frequency: VERY_FREQUENT
  notes: Due to respiratory muscle weakness, main cause of death
  phenotype_term:
    preferred_term: Respiratory Insufficiency
    term:
      id: HP:0002093
      label: Respiratory insufficiency
  evidence:
  - reference: PMID:37435300
    reference_title: "Duchenne muscular dystrophy: disease mechanism and therapeutic strategies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy."
    explanation: Review confirms respiratory insufficiency as a defining feature of DMD.
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002093 | Respiratory insufficiency | Very frequent (99-80%)"
    explanation: >-
      Orphanet classifies respiratory insufficiency as a very frequent DMD
      phenotype.
- name: Motor Delay
  category: Neurodevelopmental
  notes: >-
    Orphanet records this phenotype as Very frequent (99-80%), but this entry
    does not normalize that frequency band pending primary-literature support.
  phenotype_term:
    preferred_term: Motor Delay
    term:
      id: HP:0001270
      label: Motor delay
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001270 | Motor delay | Very frequent (99-80%)"
    explanation: >-
      Orphanet records motor delay as a DMD phenotype and supplies a
      very-frequent frequency band; the frequency band is kept as source
      context rather than a normalized dismech assertion here.
- name: Proximal Muscle Weakness
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Proximal Muscle Weakness
    term:
      id: HP:0003701
      label: Proximal muscle weakness
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0003701 | Proximal muscle weakness | Very frequent (99-80%)"
    explanation: >-
      Orphanet's curated HPO annotation classifies proximal muscle weakness as
      very frequent in DMD.
- name: Waddling Gait
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Waddling Gait
    term:
      id: HP:0002515
      label: Waddling gait
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002515 | Waddling gait | Very frequent (99-80%)"
    explanation: >-
      Orphanet's curated HPO annotation classifies waddling gait as very
      frequent in DMD.
- name: Skeletal Muscle Atrophy
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Skeletal Muscle Atrophy
    term:
      id: HP:0003202
      label: Skeletal muscle atrophy
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0003202 | Skeletal muscle atrophy | Very frequent (99-80%)"
    explanation: >-
      Orphanet's curated HPO annotation classifies skeletal muscle atrophy as
      very frequent in DMD.
- name: Flexion Contracture
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Flexion Contracture
    term:
      id: HP:0001371
      label: Flexion contracture
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001371 | Flexion contracture | Very frequent (99-80%)"
    explanation: >-
      Orphanet's curated HPO annotation classifies flexion contracture as very
      frequent in DMD.
- name: Scoliosis
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Scoliosis
    term:
      id: HP:0002650
      label: Scoliosis
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002650 | Scoliosis | Very frequent (99-80%)"
    explanation: >-
      Orphanet's curated HPO annotation classifies scoliosis as very frequent
      in DMD.
- name: Delayed Speech and Language Development
  category: Neurodevelopmental
  notes: >-
    Orphanet records this phenotype as Very frequent (99-80%), but this entry
    does not normalize that frequency band pending primary-literature support.
  phenotype_term:
    preferred_term: Delayed Speech and Language Development
    term:
      id: HP:0000750
      label: Delayed speech and language development
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000750 | Delayed speech and language development | Very frequent (99-80%)"
    explanation: >-
      Orphanet records delayed speech and language development as a DMD
      phenotype and supplies a very-frequent frequency band; the frequency band
      is kept as source context rather than a normalized dismech assertion here.
- name: Global Developmental Delay
  category: Neurodevelopmental
  notes: >-
    Orphanet records this phenotype as Very frequent (99-80%), but this entry
    does not normalize that frequency band pending primary-literature support.
  phenotype_term:
    preferred_term: Global Developmental Delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001263 | Global developmental delay | Very frequent (99-80%)"
    explanation: >-
      Orphanet records global developmental delay as a DMD phenotype and
      supplies a very-frequent frequency band; the frequency band is kept as
      source context rather than a normalized dismech assertion here.
- name: Specific Learning Disability
  category: Neurodevelopmental
  notes: >-
    Orphanet records this phenotype as Very frequent (99-80%), but this entry
    does not normalize that frequency band pending primary-literature support.
  phenotype_term:
    preferred_term: Specific Learning Disability
    term:
      id: HP:0001328
      label: Specific learning disability
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001328 | Specific learning disability | Very frequent (99-80%)"
    explanation: >-
      Orphanet records specific learning disability as a DMD phenotype and
      supplies a very-frequent frequency band; the frequency band is kept as
      source context rather than a normalized dismech assertion here.
- name: Cognitive Impairment
  category: Neurodevelopmental
  notes: >-
    Orphanet records this phenotype as Very frequent (99-80%), but this entry
    does not normalize that frequency band pending primary-literature support.
  phenotype_term:
    preferred_term: Cognitive Impairment
    term:
      id: HP:0100543
      label: Cognitive impairment
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0100543 | Cognitive impairment | Very frequent (99-80%)"
    explanation: >-
      Orphanet records cognitive impairment as a DMD phenotype and supplies a
      very-frequent frequency band; the frequency band is kept as source
      context rather than a normalized dismech assertion here.
biochemical:
- name: Creatine Kinase
  presence: Elevated
  context: Markedly elevated (10-100x normal), highest in early disease
  readouts:
  - target: Sarcolemmal Fragility
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Elevated serum CK reflects leakage from damaged skeletal muscle fibers
      and is a biochemical readout of sarcolemmal injury in DMD.
  biomarker_term:
    preferred_term: creatine kinase measurement
    term:
      id: NCIT:C64489
      label: Creatine Kinase Measurement
  evidence:
  - reference: PMID:3302699
    reference_title: "Serum creatine kinase isoenzymes in Duchenne muscular dystrophy determined by sensitive enzyme immunoassay methods."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Serum levels of creatine kinase (CK) isoenzymes (MM, MB, and BB) were
      measured by sensitive enzyme immunoassay (EIA) methods in 50 patients
      with Duchenne muscular dystrophy (DMD) and in 39 controls. MM, MB, and BB
      levels in DMD patients were higher than in controls, and these three
      levels decreased with advancing age of DMD patients.
    explanation: >-
      This patient-control enzyme-immunoassay study supports elevated serum CK
      isoenzymes as a biochemical marker of Duchenne muscular dystrophy.
- name: Dystrophin
  presence: Absent
  context: Absent or severely reduced on muscle biopsy immunostaining
  readouts:
  - target: Dystrophin Deficiency
    relationship: READOUT_OF
    direction: PRESENT_ABSENT
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Absent or severely reduced dystrophin staining directly reports the
      proximal dystrophin-deficiency mechanism.
  biomarker_term:
    preferred_term: dystrophin measurement
    term:
      id: NCIT:C209442
      label: Dystrophin Measurement
  evidence:
  - reference: PMID:2674948
    reference_title: "Dystrophin diagnosis: comparison of dystrophin abnormalities by immunofluorescence and immunoblot analyses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      There was a very strong correlation of clinical diagnoses with the type of
      dystrophin abnormality; all Duchenne muscular dystrophy patient muscle
      contained no detectable dystrophin, Becker muscular dystrophy patient
      muscle had clearly abnormal dystrophin, and unrelated diseases showed
      normal dystrophin.
    explanation: >-
      Immunoblot and immunofluorescence testing in human muscle directly
      supports absent dystrophin as a Duchenne biochemical diagnostic marker.
- name: Treatment-Induced Dystrophin Expression
  presence: Treatment-induced
  context: >-
    Measured in skeletal muscle biopsy after exon-skipping antisense
    oligonucleotide therapy; distinct from baseline diagnostic absence of
    dystrophin.
  readouts:
  - target: Dystrophin Deficiency
    relationship: PHARMACODYNAMIC_MARKER_OF
    direction: PRESENT_ABSENT
    endpoint_context: PHARMACODYNAMIC
    regulatory_endpoint_refs:
    - FDA-SE-adult-noncancer-022
    - FDA-SE-pediatric-noncancer-017
    interpretation: >-
      Treatment-induced dystrophin expression in skeletal muscle reports
      pharmacodynamic correction at the dystrophin-deficiency node for
      exon-skipping therapies.
  biomarker_term:
    preferred_term: dystrophin measurement
    term:
      id: NCIT:C209442
      label: Dystrophin Measurement
  synonyms:
  - skeletal muscle dystrophin
  - exon-skipping-induced dystrophin
  evidence:
  - reference: PMID:29752304
    reference_title: "Eteplirsen treatment for Duchenne muscular dystrophy: Exon skipping and dystrophin production."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Taken together, the 4 assays, each based on unique evaluation mechanisms,
      provided evidence of eteplirsen muscle cell penetration, exon skipping,
      and induction of novel dystrophin expression.
    explanation: >-
      This eteplirsen study supports treatment-induced dystrophin expression as
      a measured pharmacodynamic biomarker for exon-skipping therapy in DMD.
- name: Micro-dystrophin Expression
  presence: Treatment-induced
  context: >-
    Measured in muscle biopsy after delandistrogene moxeparvovec gene therapy;
    distinguish from endogenous full-length dystrophin.
  readouts:
  - target: Dystrophin Deficiency
    relationship: PHARMACODYNAMIC_MARKER_OF
    direction: PRESENT_ABSENT
    endpoint_context: PHARMACODYNAMIC
    interpretation: >-
      Treatment-induced micro-dystrophin expression reports biological response
      at the dystrophin-deficiency node rather than baseline disease status.
  biomarker_term:
    preferred_term: dystrophin measurement
    term:
      id: NCIT:C209442
      label: Dystrophin Measurement
  synonyms:
  - delandistrogene moxeparvovec micro-dystrophin
  evidence:
  - reference: PMID:37539981
    reference_title: "Delandistrogene Moxeparvovec Gene Therapy in Ambulatory Patients (Aged ≥4 to <8 Years) with Duchenne Muscular Dystrophy: 1-Year Interim Results from Study SRP-9001-103 (ENDEAVOR)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The primary endpoint was change from baseline (CFBL) to week 12 in
      delandistrogene moxeparvovec micro-dystrophin by western blot. Additional
      endpoints evaluated included: safety; vector genome copies; CFBL to week
      12 in muscle fiber-localized micro-dystrophin by immunofluorescence; and
      functional assessments, including North Star Ambulatory Assessment, with
      comparison with a propensity score-weighted external natural history
      control.
    explanation: >-
      The ENDEAVOR DMD gene-therapy study used micro-dystrophin expression in
      muscle biopsy as a measured biochemical endpoint.
- name: N-terminal Titin Fragment
  presence: Treatment-responsive
  context: >-
    Urinary N-terminal titin fragment measured by proteomic profiling;
    pharmacodynamic biomarker of microdystrophin gene-therapy efficacy. More
    sensitive than serum CK at low levels of expressed microdystrophin.
  readouts:
  - target: Sarcolemmal Fragility
    relationship: PHARMACODYNAMIC_MARKER_OF
    direction: NEGATIVE
    endpoint_context: PHARMACODYNAMIC
    interpretation: >-
      Reduction in urinary N-terminal titin fragment levels reports
      pharmacodynamic correction of myofiber membrane injury after AAV
      microdystrophin restoration.
  biomarker_term:
    preferred_term: urinary N-terminal titin fragment
    term:
      id: NCIT:C101758
      label: Titin
  synonyms:
  - urinary titin
  - N-terminal titin fragment
  evidence:
  - reference: PMID:38229112
    reference_title: "N-terminal titin fragment: a non-invasive, pharmacodynamic biomarker for microdystrophin efficacy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Potential PD biomarkers in DMD participant urine were examined using a
      proteomic approach on the Somalogic platform.
    explanation: >-
      Identifies urinary N-terminal titin fragment as a candidate
      pharmacodynamic biomarker in human DMD participants via Somalogic
      proteomic profiling.
  - reference: PMID:38229112
    reference_title: "N-terminal titin fragment: a non-invasive, pharmacodynamic biomarker for microdystrophin efficacy."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Findings were confirmed in both mdx mice and Golden Retriever muscular
      dystrophy (GRMD) dog plasma samples.
    explanation: >-
      mdx mouse and GRMD dog plasma data confirm cross-species reproducibility
      of titin fragment changes as a DMD biomarker.
  - reference: PMID:38229112
    reference_title: "N-terminal titin fragment: a non-invasive, pharmacodynamic biomarker for microdystrophin efficacy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The measurement of objective PD biomarkers such as titin may provide
      additional confidence in the assessment of the mechanism of action and
      efficacy in gene therapy clinical trials of DMD.
    explanation: >-
      Author conclusion positions titin as a pharmacodynamic biomarker to
      complement functional outcome measures in DMD gene therapy trials.
genetic:
- name: DMD pathogenic variants
  gene_term:
    preferred_term: DMD
    term:
      id: hgnc:2928
      label: DMD
  association: Causative loss-of-function variants
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: X-linked recessive
    evidence:
    - reference: PMID:23650001
      reference_title: "Two mutations in one dystrophin gene."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Duchenne/Becker muscular dystrophies (DMD/BMD) lead to progressive
        irreversible muscle deterioration caused by recessive mutations in the
        dystrophin encoding gene (Xp21.1).
      explanation: >-
        The cited human-family study places the recessive causal gene at the
        Xp21.1 dystrophin locus, consistent with X-linked recessive inheritance.
  variants:
  - name: Out-of-frame or truncating DMD variants
    description: >-
      Duchenne-associated deletions, duplications, nonsense variants,
      frameshifts, and splice variants commonly disrupt the DMD reading frame
      and produce prematurely truncated or dysfunctional dystrophin.
    gene:
      preferred_term: DMD
      term:
        id: hgnc:2928
        label: DMD
    clinical_significance: PATHOGENIC
    type: loss_of_function_variant
    functional_effects:
    - function: Dystrophin production
      description: Premature truncation or severe loss of functional dystrophin.
      type: loss-of-function
    evidence:
    - reference: PMID:16770791
      reference_title: "Entries in the Leiden Duchenne muscular dystrophy mutation database: an overview of mutation types and paradoxical cases that confirm the reading-frame rule."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In Duchenne patients, mutations induce a shift in the reading frame
        leading to prematurely truncated, dysfunctional dystrophins.
      explanation: >-
        This mutation-database review directly supports out-of-frame/truncating
        DMD variants as the severe Duchenne molecular class.
  - name: DMD exon deletions
    description: >-
      Multiexon or single-exon deletions are the most frequent DMD mutation
      class and often cause Duchenne disease when they disrupt the reading
      frame.
    gene:
      preferred_term: DMD
      term:
        id: hgnc:2928
        label: DMD
    clinical_significance: PATHOGENIC
    type: copy_number_loss
    functional_effects:
    - function: Dystrophin open reading frame
      description: Exon loss can disrupt the open reading frame and abolish functional dystrophin.
      type: loss-of-function
    evidence:
    - reference: PMID:23650001
      reference_title: "Two mutations in one dystrophin gene."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Approximately 60% of mutations are deletions, 10% are duplications and
        the remaining 30% are point mutations.
      explanation: >-
        This provides the reported relative frequency of deletions among
        dystrophinopathy-causing DMD mutations.
  - name: DMD exon duplications
    description: >-
      DMD exon duplications are a recurrent copy-number class. Their clinical
      effect depends on transcript structure and whether the duplication
      disrupts the reading frame.
    gene:
      preferred_term: DMD
      term:
        id: hgnc:2928
        label: DMD
    clinical_significance: PATHOGENIC
    type: copy_number_gain
    functional_effects:
    - function: Dystrophin open reading frame
      description: Exon gain can disrupt transcript structure or the reading frame.
      type: loss-of-function
    evidence:
    - reference: PMID:23650001
      reference_title: "Two mutations in one dystrophin gene."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Approximately 60% of mutations are deletions, 10% are duplications and
        the remaining 30% are point mutations.
      explanation: >-
        This supports duplications as a recurring DMD mutation class.
  - name: DMD point and small sequence variants
    description: >-
      Nonsense, frameshift, splice-site, and other small sequence variants
      account for the remaining major DMD mutation class and can cause the
      Duchenne phenotype when they truncate or destabilize dystrophin.
    gene:
      preferred_term: DMD
      term:
        id: hgnc:2928
        label: DMD
    clinical_significance: PATHOGENIC
    type: sequence_variant
    functional_effects:
    - function: Dystrophin protein integrity
      description: Small sequence changes can truncate or severely impair dystrophin.
      type: loss-of-function
    evidence:
    - reference: PMID:23650001
      reference_title: "Two mutations in one dystrophin gene."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Approximately 60% of mutations are deletions, 10% are duplications and
        the remaining 30% are point mutations.
      explanation: >-
        This supports point and small sequence variants as a major non-CNV DMD
        mutation class.
  features: >-
    DMD is an X-linked dystrophinopathy in which Duchenne severity usually
    follows the reading-frame rule: out-of-frame or truncating variants abolish
    functional dystrophin, while in-frame variants can preserve partially
    functional dystrophin and cause milder Becker or intermediate phenotypes.
    Variant class determines eligibility for mutation-specific therapies such
    as exon skipping or stop-codon readthrough.
  notes: >-
    Contemporary cohort data continue to show that exonic deletions are the
    most common mutation class, followed by duplications and truncating or
    splice-disrupting sequence variants. Genotype-phenotype prediction is strong
    but not absolute because transcript processing, residual dystrophin, and
    mutation position can modify severity.
  evidence:
  - reference: DOI:10.1186/s13023-024-03217-7
    reference_title: "Comprehensive analysis of 2097 patients with dystrophinopathy based on a database from 2011 to 2021"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The spectrum of identified variants included exonic deletions (66.6%),
      exonic duplications (10.7%), nonsense variants (10.3%), splice-site
      variants (4.5%), small deletions (3.5%), small insertions/duplications
      (1.8%), and missense variants (0.9%).
    explanation: >-
      This recent 2,097-patient dystrophinopathy cohort updates the DMD variant
      spectrum and supports the curated mutation-class distribution.
  - reference: PMID:16770791
    reference_title: "Entries in the Leiden Duchenne muscular dystrophy mutation database: an overview of mutation types and paradoxical cases that confirm the reading-frame rule."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Currently, over 4700 mutations have been reported in the Leiden DMD
      mutation database, of which 91% are in agreement with this rule.
    explanation: >-
      This supports the reading-frame rule as the major genotype-phenotype
      principle while acknowledging known exceptions.
- name: LTBP4 modifier variants
  gene_term:
    preferred_term: LTBP4
    term:
      id: hgnc:6717
      label: LTBP4
  association: Genetic modifier of DMD severity
  relationship_type: MODIFIER
  variant_origin: GERMLINE
  notes: >-
    Orphanet lists LTBP4 as a modifying germline mutation in Duchenne muscular
    dystrophy; this entry captures modifier status rather than primary
    causation.
  evidence:
  - reference: ORPHA:98896
    reference_title: "Duchenne muscular dystrophy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "LTBP4 | latent transforming growth factor beta binding protein 4 | hgnc:6717 | Modifying germline mutation in"
    explanation: >-
      Orphanet's genes table lists LTBP4 with a modifying germline-mutation
      relationship for the Duchenne muscular dystrophy record.
treatments:
- name: Corticosteroids
  description: Prednisone or deflazacort to slow muscle degeneration and prolong ambulation.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: prednisone
      term:
        id: CHEBI:8382
        label: prednisone
    - preferred_term: deflazacort
      term:
        id: CHEBI:135720
        label: deflazacort
  evidence:
  - reference: PMID:15106215
    reference_title: "Glucocorticoid corticosteroids for Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "There is evidence from randomised controlled studies that glucocorticoid corticosteroid therapy in Duchenne muscular dystrophy improves muscle strength and function in the short-term (six months to two years)."
    explanation: Cochrane review confirms corticosteroids improve muscle strength and function in DMD.
  - reference: PMID:22581531
    reference_title: "Early corticosteroid treatment in 4 Duchenne muscular dystrophy patients: 14-year follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Long-term corticosteroid treatment is effective in prolonging function but not in recovering lost function, and its early use seems appropriate."
    explanation: Long-term follow-up study confirms corticosteroids prolong function in DMD.
- name: Cardiac Management
  description: ACE inhibitors and beta-blockers for cardiomyopathy prevention and treatment.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: ACE inhibitor
      term:
        id: NCIT:C247
        label: ACE Inhibitor
    - preferred_term: beta-adrenergic antagonist
      term:
        id: NCIT:C29576
        label: Beta-Adrenergic Antagonist
  evidence:
  - reference: PMID:22463839
    reference_title: "Effects of angiotensin-converting enzyme inhibitors and/or beta blockers on the cardiomyopathy in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Treatment with ACE inhibitor or ACE inhibitor plus BB resulted in significant improvement compared to pretherapy."
    explanation: Study demonstrates ACE inhibitors improve cardiac function in DMD patients.
  - reference: PMID:19167641
    reference_title: "Beneficial effects of beta-blockers and angiotensin-converting enzyme inhibitors in Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In this study, the combination of an ACE inhibitor and a beta-blocker had a beneficial effect on long-term survival of DMD patients with heart failure."
    explanation: Study shows ACE inhibitor plus beta-blocker combination improves survival in DMD.
- name: Respiratory Support
  description: Non-invasive ventilation as respiratory function declines.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
- name: Eteplirsen (Exon 51 Skipping)
  description: >-
    Phosphorodiamidate morpholino antisense oligonucleotide that induces skipping
    of DMD exon 51, restoring the reading frame in patients with deletions amenable
    to exon 51 skipping and producing internally truncated but functional dystrophin.
  therapeutic_modality: ANTISENSE_OLIGONUCLEOTIDE
  aso_details:
    aso_mechanism: SPLICE_MODULATION_EXON_SKIPPING
    target_gene:
      preferred_term: DMD
      term:
        id: hgnc:2928
        label: DMD
    target_transcript: DMD pre-mRNA
    target_exon: exon 51
    aso_chemistry: PHOSPHORODIAMIDATE_MORPHOLINO
    conjugation: UNCONJUGATED
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: eteplirsen
      term:
        id: NCIT:C171739
        label: Eteplirsen
  evidence:
  - reference: PMID:29752304
    reference_title: "Eteplirsen treatment for Duchenne muscular dystrophy: Exon skipping and dystrophin production."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In treated patients vs untreated controls, Western blot analysis of dystrophin content demonstrated an 11.6-fold increase (p = 0.007), and PDPF analysis demonstrated a 7.4-fold increase (p < 0.001)."
    explanation: Clinical study demonstrates eteplirsen induces dystrophin production in DMD patients.
- name: Golodirsen (Exon 53 Skipping)
  description: >-
    Phosphorodiamidate morpholino antisense oligonucleotide that induces skipping
    of DMD exon 53, restoring the reading frame in patients with deletions amenable
    to exon 53 skipping.
  therapeutic_modality: ANTISENSE_OLIGONUCLEOTIDE
  aso_details:
    aso_mechanism: SPLICE_MODULATION_EXON_SKIPPING
    target_gene:
      preferred_term: DMD
      term:
        id: hgnc:2928
        label: DMD
    target_transcript: DMD pre-mRNA
    target_exon: exon 53
    aso_chemistry: PHOSPHORODIAMIDATE_MORPHOLINO
    conjugation: UNCONJUGATED
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    therapeutic_agent:
    - preferred_term: golodirsen
      term:
        id: NCIT:C175077
        label: Golodirsen
  evidence:
  - reference: PMID:32139505
    reference_title: "Increased dystrophin production with golodirsen in patients with Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "muscle biopsies from golodirsen-treated patients showed increased exon 53 skipping, dystrophin production, and correct dystrophin sarcolemmal localization."
    explanation: SKIP-NMD trial shows golodirsen induces exon 53 skipping and increased sarcolemmal dystrophin in DMD patients amenable to exon 53 skipping.
- name: Viltolarsen (Exon 53 Skipping)
  description: >-
    Phosphorodiamidate morpholino antisense oligonucleotide that induces skipping
    of DMD exon 53, restoring the reading frame in patients with deletions amenable
    to exon 53 skipping.
  therapeutic_modality: ANTISENSE_OLIGONUCLEOTIDE
  aso_details:
    aso_mechanism: SPLICE_MODULATION_EXON_SKIPPING
    target_gene:
      preferred_term: DMD
      term:
        id: hgnc:2928
        label: DMD
    target_transcript: DMD pre-mRNA
    target_exon: exon 53
    aso_chemistry: PHOSPHORODIAMIDATE_MORPHOLINO
    conjugation: UNCONJUGATED
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    therapeutic_agent:
    - preferred_term: viltolarsen
      term:
        id: NCIT:C170393
        label: Viltolarsen
  evidence:
  - reference: PMID:32453377
    reference_title: "Safety, Tolerability, and Efficacy of Viltolarsen in Boys With Duchenne Muscular Dystrophy Amenable to Exon 53 Skipping: A Phase 2 Randomized Clinical Trial."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "After 20 to 24 weeks of treatment, significant drug-induced dystrophin production was seen in both viltolarsen dose cohorts"
    explanation: Phase 2 RCT shows viltolarsen induces de novo dystrophin production in DMD patients amenable to exon 53 skipping.
- name: Ataluren Stop-Codon Readthrough Therapy
  description: >-
    Ataluren plus standard care promotes readthrough of premature stop codons
    for ambulatory patients with nonsense mutation DMD, delaying functional and
    respiratory disease-progression milestones.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: ataluren
      term:
        id: CHEBI:94805
        label: 3-[5-(2-fluorophenyl)-1,2,4-oxadiazol-3-yl]benzoic acid
  evidence:
  - reference: DOI:10.1007/s00415-023-11687-1
    reference_title: "Safety and effectiveness of ataluren in patients with nonsense mutation DMD in the STRIDE Registry compared with the CINRG Duchenne Natural History Study (2015–2022): 2022 interim analysis"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Kaplan–Meier analyses demonstrated that ataluren plus SoC significantly
      delayed age at loss of ambulation by 4 years (p < 0.0001) and age at
      decline to %-predicted forced vital capacity of < 60% and < 50% by
      1.8 years (p = 0.0021) and 2.3 years (p = 0.0207), respectively, compared
      with SoC alone.
    explanation: >-
      The STRIDE registry compared ataluren plus standard care with CINRG
      natural-history standard care and showed delayed loss of ambulation and
      respiratory decline milestones in nonsense-mutation DMD.
- name: Gene Therapy
  description: Micro-dystrophin gene delivery via AAV vectors in clinical trials.
  treatment_term:
    preferred_term: gene therapy
    term:
      id: MAXO:0001001
      label: gene therapy
- name: Sevasemten (EDG-5506)
  description: >-
    Selective, orally active allosteric inhibitor of fast skeletal muscle
    myosin (Edgewise Therapeutics; investigational). Modest reduction of
    fast-fiber contraction is sufficient to protect dystrophin-deficient
    muscle from contraction-induced membrane injury without compromising
    overall strength or coordination.
  treatment_term:
    preferred_term: fast skeletal muscle myosin allosteric inhibitor
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
  target_mechanisms:
  - target: Sarcolemmal Fragility
    treatment_effect: INHIBITS
    description: >-
      Modulating fast skeletal muscle contraction reduces the mechanical
      stress experienced by the dystrophin-deficient sarcolemma, protecting
      fragile fast fibers from contraction-induced membrane injury.
    evidence:
    - reference: PMID:36995778
      reference_title: "Modulating fast skeletal muscle contraction protects skeletal muscle in animal models of Duchenne muscular dystrophy."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "even modest decreases of contraction (<15%) were sufficient to protect skeletal muscles in dystrophic mdx mice from stress injury"
      explanation: >-
        Demonstrates that reducing fast-fiber contraction with EDG-5506
        protects dystrophic muscle from mechanical-stress-induced injury,
        the proximate consequence of sarcolemmal fragility.
  evidence:
  - reference: PMID:36995778
    reference_title: "Modulating fast skeletal muscle contraction protects skeletal muscle in animal models of Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "We explored the role of fast skeletal muscle contraction in DMD with a potentially novel, selective, orally active inhibitor of fast skeletal muscle myosin, EDG-5506."
    explanation: >-
      Identifies EDG-5506 (sevasemten) as a selective, orally active
      inhibitor of fast skeletal muscle myosin used to interrogate
      contraction's contribution to DMD pathophysiology.
  - reference: PMID:36995778
    reference_title: "Modulating fast skeletal muscle contraction protects skeletal muscle in animal models of Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Longer-term treatment also decreased muscle fibrosis in key disease-implicated tissues."
    explanation: >-
      Sustained fast-myosin inhibition reduces downstream fibrotic
      remodeling in dystrophic skeletal muscle, supporting a
      disease-modifying effect beyond acute membrane protection.
  - reference: PMID:36995778
    reference_title: "Modulating fast skeletal muscle contraction protects skeletal muscle in animal models of Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "in dystrophic dogs, EDG-5506 reversibly reduced circulating muscle injury biomarkers and increased habitual activity."
    explanation: >-
      Cross-species replication in the GRMD dog model shows reduction of
      circulating muscle injury biomarkers and increased habitual
      activity with EDG-5506 treatment.
  - reference: PMID:36995778
    reference_title: "Modulating fast skeletal muscle contraction protects skeletal muscle in animal models of Duchenne muscular dystrophy."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "therapeutic levels of myosin inhibition with EDG-5506 did not detrimentally affect strength or coordination."
    explanation: >-
      Establishes the therapeutic window: contraction modulation that
      protects fragile dystrophic fibers does not compromise overall
      muscle strength or motor coordination in animal models.
- name: Agents/Circumstances to Avoid
  description: >-
    Botulinum toxin injections are contraindicated. Succinylcholine and
    inhalational anesthetics should be avoided due to susceptibility to
    malignant hyperthermia or malignant hyperthermia-like reactions.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  evidence:
  - reference: PMID:20301298
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Agents/circumstances to avoid: Botulinum toxin injections; succinylcholine and inhalational anesthetics because of susceptibility to malignant hyperthermia or malignant hyperthermia-like reactions."
    explanation: >-
      GeneReviews explicitly lists botulinum toxin, succinylcholine, and
      inhalational anesthetics as agents/circumstances to avoid in
      dystrophinopathies due to malignant hyperthermia susceptibility.
clinical_trials:
- name: NCT05540860
  phase: PHASE_II
  status: ACTIVE_NOT_RECRUITING
  description: >-
    LYNX — 2-part, multicenter, Phase 2 study of safety, pharmacokinetics
    and biomarkers of sevasemten (EDG-5506) in children with Duchenne
    muscular dystrophy. Randomized, double-blind, placebo-controlled Part A
    followed by an open-label Part B.
  evidence:
  - reference: clinicaltrials:NCT05540860
    supports: SUPPORT
    snippet: "The LYNX study is a 2-part, multicenter, Phase 2 study of safety, pharmacokinetics and biomarkers in children with Duchenne muscular dystrophy including a randomized, double-blind, placebo-controlled part A, followed by an open-label part B."
    explanation: >-
      ClinicalTrials.gov record for the pediatric DMD Phase 2 trial of
      sevasemten (EDG-5506) — the clinical translation of the
      preclinical mechanism reported in PMID:36995778.
discussions:
- discussion_id: gap_dmd_microdystrophin_fibrosis_reversal
  prompt: >-
    Does restored dystrophin or microdystrophin expression reverse established
    skeletal-muscle and myocardial fibrosis in DMD, or does it mainly stabilize
    sarcolemmal injury before fibrotic remodeling becomes self-sustaining?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Dystrophin Deficiency
  - pathophysiology#Sarcolemmal Fragility
  - pathophysiology#Fibrofatty Muscle Replacement
  - pathophysiology#Myocardial Fibrosis
  rationale: >-
    The entry already captures dystrophin loss, membrane fragility, chronic
    degeneration, and fibrofatty replacement. Recent human engineered-muscle
    work suggests that membrane stabilization and profibrotic signaling can
    decouple, making the reversibility of established fibrosis a distinct
    therapeutic knowledge gap rather than a simple proxy for dystrophin
    expression.
  proposed_experiments:
  - experiment_id: exp_dmd_fibrotic_myorganoid_microdystrophin_rescue
    name: Fibrotic patient-derived DMD MYOrganoid microdystrophin rescue assay
    description: >-
      Build patient-derived iPSC skeletal-muscle MYOrganoids with a fibroblast
      niche and induced fibrotic maturation, deliver microdystrophin before or
      after fibrotic priming, and compare membrane stability, contractile
      fatigue, and extracellular-matrix remodeling.
    experiment_type:
      preferred_term: patient-derived organoid perturbation experiment
    model_systems:
    - name: Patient-derived DMD skeletal-muscle MYOrganoid with fibroblast niche
      description: >-
        Three-dimensional iPSC-derived skeletal-muscle organoid containing
        fibroblasts so dystrophic membrane injury, repeated-contraction fatigue,
        and profibrotic muscle-fibroblast signaling can be measured in the same
        standardized human model.
      experimental_model_type: ORGANOID
      namo_type: namo:Organoid
      organism:
        preferred_term: human
        term:
          id: NCBITaxon:9606
          label: Homo sapiens
      tissue_term:
        preferred_term: skeletal muscle tissue
        term:
          id: UBERON:0001134
          label: skeletal muscle tissue
      cell_types:
      - preferred_term: skeletal muscle cell
      - preferred_term: fibroblast
        term:
          id: CL:0000057
          label: fibroblast
      cell_source: patient-derived iPSC-derived myogenic cells plus matched fibroblasts
      culture_system: collagen-based 3D engineered muscle ring with eccentric-contraction challenge
    perturbations:
    - name: Microdystrophin gene transfer
      target: pathophysiology#Dystrophin Deficiency
      description: >-
        AAV-like microdystrophin delivery or matched genetic rescue used to
        restore dystrophin-family membrane support in the engineered tissue.
      treatment_term:
        preferred_term: gene therapy
        term:
          id: MAXO:0001001
          label: gene therapy
    - name: Fibrotic niche priming
      target: pathophysiology#Fibrofatty Muscle Replacement
      description: >-
        Fibroblast-containing dystrophic culture conditions, optionally with
        TGF-beta pathway stimulation, used to establish a profibrotic baseline
        before rescue.
      biological_processes:
      - preferred_term: extracellular matrix organization
        term:
          id: GO:0030198
          label: extracellular matrix organization
    readouts:
    - name: Sarcolemmal membrane stability
      target: pathophysiology#Sarcolemmal Fragility
      description: Dye-exclusion or membrane-leak readout after eccentric contraction.
      assays:
      - preferred_term: membrane permeability assay
      direction: NEGATIVE
    - name: Contractile force and fatigue resistance
      target: pathophysiology#Progressive Muscle Degeneration
      description: Electrical-stimulation force and fatigue readouts in matched tissue rings.
      assays:
      - preferred_term: contractility assay
      direction: NEGATIVE
    - name: Profibrotic extracellular-matrix signaling
      target: pathophysiology#Fibrofatty Muscle Replacement
      description: >-
        Collagen, fibronectin, and TGF-beta-responsive transcriptional readouts
        interpreted as persistence or resolution of fibrotic remodeling.
      biological_processes:
      - preferred_term: extracellular matrix organization
        term:
          id: GO:0030198
          label: extracellular matrix organization
      assays:
      - preferred_term: single-cell transcriptomic profiling
      - preferred_term: extracellular matrix immunostaining
      direction: NEGATIVE
    controls:
    - name: Isogenic corrected MYOrganoid
      description: DMD-corrected tissue carrying the same genetic background.
    - name: Empty-vector DMD MYOrganoid
      description: Dystrophic organoid receiving vector or delivery control without microdystrophin.
    decision_criterion: >-
      Reversal is supported if delayed microdystrophin rescue improves membrane
      stability and contractile fatigue while reducing profibrotic
      extracellular-matrix readouts toward isogenic-corrected levels.
      Stabilization-only is supported if membrane and force readouts improve
      but fibrotic signaling remains elevated.
    would_support:
    - pathophysiology#Sarcolemmal Fragility
    - pathophysiology#Fibrofatty Muscle Replacement
    - pathophysiology#Myocardial Fibrosis
    evidence:
    - reference: DOI:10.1038/s41536-025-00445-8
      reference_title: "Disease exacerbation in human DMD MYOrganoids enables gene therapy evaluation and unveils persistence of fibrotic activity"
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "recapitulating critical hallmarks of DMD, such as fibrosis and muscle dysfunction"
      explanation: >-
        Provides the recent human organoid precedent for testing DMD fibrosis
        and muscle dysfunction in a fibroblast-containing engineered tissue.
    - reference: DOI:10.1038/s41536-025-00445-8
      reference_title: "Disease exacerbation in human DMD MYOrganoids enables gene therapy evaluation and unveils persistence of fibrotic activity"
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "it fails to reduce profibrotic signaling"
      explanation: >-
        Motivates the specific knowledge gap: restored microdystrophin activity
        may not be sufficient to extinguish established fibrotic signaling.
    - reference: PMID:29752304
      reference_title: "Eteplirsen treatment for Duchenne muscular dystrophy: Exon skipping and dystrophin production."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Western blot analysis of dystrophin content demonstrated an 11.6-fold increase"
      explanation: >-
        Shows that dystrophin-expression restoration can be measured clinically,
        but does not by itself resolve fibrosis-reversal mechanisms.
references:
- reference: PMID:20301298
  title: "Dystrophinopathies."
  tags:
  - GeneReviews
  findings: []

📚

References & Deep Research

References

1

PMID:20301298

Dystrophinopathies.

No top-level findings curated for this source.

Deep Research

1

Falcon ▸

Disease Characteristics Research Template

Edison Scientific Literature 48 citations 2026-04-25T22:25:51.675950

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

Disease Name: Duchenne Muscular Dystrophy
MONDO ID: (if available)
Category: Genetic

Research Objectives

Please provide a comprehensive research report on Duchenne Muscular Dystrophy covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

What is the disease? Provide a concise overview.
What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
What are the common synonyms and alternative names?
Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
Risk Factors:

Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases
Genetic risk factors (causal variants, susceptibility loci, modifier genes)
Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
Protective Factors:

Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases
Genetic protective factors (protective variants, modifier alleles)
Environmental protective factors (diet, lifestyle, exposures that reduce risk)
Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
Pathogenic Variants:
Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
Variant type/class (missense, frameshift, nonsense, splice-site, structural)
Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
Functional consequences (loss of function, gain of function, dominant negative)
Modifier Genes: Genes that modify disease severity or expression
Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases
Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

Search first: CDC databases, WHO, PubMed, NHANES
Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc
Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

Search first: Gene Ontology (GO), Reactome, KEGG, PubMed
Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold
Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA
Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

Search first: ImmPort, Immunome Database, IEDB, Gene Ontology
Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

Search first: PubMed, Gene Ontology, Reactome
Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Molecular Profiling (if available):
Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
Advanced Technologies (if applicable):
Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

Organ Level:
Primary organs directly affected
Secondary organ involvement (complications, secondary effects)
Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
Tissue and Cell Level:
Specific tissue types affected (epithelial, connective, muscle, nervous)
Specific cell populations targeted (with Cell Ontology terms)

Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
Subcellular Level:
Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
Localization:
Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

Onset:
Typical age of onset (congenital, pediatric, adult, geriatric)
Onset pattern (acute, subacute, chronic, insidious)

Search first: OMIM, Orphanet, HPO, PubMed
Progression:
Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
Progression rate (rapid, slow, variable)
Disease course pattern (episodic, relapsing-remitting, progressive, stable)
Disease duration (self-limited, chronic lifelong)

Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
Patterns:
Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

Epidemiology:
Prevalence (cases per 100,000 at given time)
Incidence (new cases per 100,000 per year)

Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
For Genetic Etiology:
Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
Population Demographics:
Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
Geographic distribution of specific variants
Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

Clinical Tests:
Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
Genetic Testing:

Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
Overview of recommended genetic testing approach
Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
FISH > Search first: ClinVar, cytogenetics databases, PubMed
Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
Omics-Based Diagnostics (if applicable):
RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
Clinical Criteria:
Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
Screening:
Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

Survival and Mortality:
Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
Morbidity and Function:
Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
Disease Course:
Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
Prediction:
Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

Pharmacotherapy:
Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
Advanced Therapeutics:
Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
Surgical and Interventional:
Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
Supportive and Rehabilitative:
Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
Experimental:
Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
Treatment Outcomes:
Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
Treatment Strategy:
Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

Prevention Levels:
Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
Immunization: Vaccine strategies (if applicable)

Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
Screening and Early Detection:
Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
Behavioral Interventions: Lifestyle modifications to reduce risk

Search first: CDC, WHO, behavioral intervention databases, Cochrane Library
Counseling: Genetic counseling (risk assessment, family planning guidance)

Search first: NSGC resources, ACMG guidelines, GeneReviews
Public Health:
Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
Prophylaxis: Preventive medications or procedures

Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

Taxonomy: Species affected (with NCBI Taxon identifiers)

Search first: NCBI Taxonomy
Breed: Specific breeds affected (with VBO identifiers if applicable)

Search first: VBO (Vertebrate Breed Ontology)
Gene: Orthologous genes in other species (with NCBI Gene IDs)

Search first: NCBI Gene
Natural Disease:
Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
Comparative Biology:
Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
Transmission (if applicable):
Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

Model Types:
Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
Genetic Models:
Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
Model Characteristics:
Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
Applications:
Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
Resources:
Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

Cite primary literature (PMID preferred) for all mechanistic and clinical claims
Prioritize recent reviews and landmark papers
Include direct quotes from abstracts where possible to support key statements
Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Duchenne Muscular Dystrophy (DMD): Disease Characteristics Research Report (2023–2025 evidence prioritized)

Executive summary

Duchenne muscular dystrophy (DMD) is a severe X‑linked recessive dystrophinopathy caused by pathogenic variants in the DMD gene that eliminate functional dystrophin, leading to progressive skeletal muscle degeneration with cardiomyopathy and respiratory failure as major life‑limiting complications. Contemporary registries, claims datasets, and consensus guidelines show: (i) substantial variability in prevalence estimates across countries (roughly ~1.65/100,000 overall in a genetically strict Italian survey vs ~3.23/100,000 in an English claims analysis) (capasso2024prevalenceofduchenne pages 1-2, morgan2024epidemiologyandhealthcare pages 1-2); (ii) respiratory and cardiac management materially affect survival and causes of death (wahlgren2024respiratorycomorbiditiesand pages 1-2); and (iii) the therapeutic landscape is expanding (ataluren real‑world milestone delays in nonsense‑mutation DMD; AAV micro‑dystrophin gene transfer with defined adverse event profiles and management pathways) (mercuri2023safetyandeffectiveness pages 1-2, zaidman2024managementofselect pages 8-11).

A summary of key recent studies/guidelines used in this report is provided in the embedded table.

Domain	Citation	Publication date	Key quantitative findings	URL	Evidence type
Epidemiology	Capasso et al., 2024, European Journal of Pediatrics	12/2024	• Nationwide Italian prevalence: 1.65/100,000 overall; 3.4/100,000 males • Cohort n=972; 57% non-ambulant; ~73% no ventilatory support (capasso2024prevalenceofduchenne pages 5-8, capasso2024prevalenceofduchenne pages 1-2)	https://doi.org/10.1007/s00431-024-05903-x	Nationwide survey/registry-style prevalence study
Epidemiology	Morgan et al., 2024, Journal of Rare Diseases	08/2024	• England point prevalence (2020): 3.23/100,000 (95% CI 2.82–3.63) • Utilization vs controls: inpatient IRR 9.24, outpatient IRR 11.44; adjusted cost ratio 9.33 (morgan2024epidemiologyandhealthcare pages 1-2)	https://doi.org/10.1007/s44162-024-00044-z	Claims database study
Epidemiology / prognosis	Wahlgren et al., 2024, Journal of Neurology	04/2024	• Swedish mortality cohort median lifespan: 24.3 years • 70.1% had ≥1 pneumonia; 73.0% developed hypoventilation; acute respiratory failure caused 63.3% of respiratory-related deaths (wahlgren2024respiratorycomorbiditiesand pages 1-2)	https://doi.org/10.1007/s00415-024-12372-7	National mortality cohort / registry-linked study
Genetics / natural history	Zhao et al., 2024, Orphanet Journal of Rare Diseases	08/2024	• Cohort n=2,097 dystrophinopathy patients, including 1,703 DMD • Variant spectrum: deletions 66.6%, duplications 10.7%, nonsense 10.3%; glucocorticoids delayed loss of ambulation by median 2.5 years (zhao2024comprehensiveanalysisof pages 1-2)	https://doi.org/10.1186/s13023-024-03217-7	Large single-center cohort/database study
Respiratory care	Childs et al., 2024, Thorax	12/2024	• Respiratory monitoring recommended every 6–12 months when ambulatory and every 6 months when non-ambulatory • FVC ≤50% predicted should remain under respiratory review; NIV considered with hypoxemia <95% or hypercapnia >45 mmHg/6 kPa (childs2024developmentofrespiratory pages 6-7, childs2024developmentofrespiratory pages 3-3, childs2024developmentofrespiratory pages 1-2)	https://doi.org/10.1136/thorax-2023-220811	Consensus guideline
Treatment—ataluren	Mercuri et al., 2023, Journal of Neurology	04/2023	• STRIDE registry enrolled 307 patients from 14 countries; mean ataluren exposure 1,671 days • Ataluren + standard care delayed loss of ambulation by 4.0 years and delayed FVC decline <60% by 1.8 years, <50% by 2.3 years (mercuri2023safetyandeffectiveness pages 1-2, mercuri2023safetyandeffectiveness pages 10-11, mercuri2023safetyandeffectiveness pages 6-7)	https://doi.org/10.1007/s00415-023-11687-1	International registry / real-world comparative study
Treatment—AAV gene therapy	Zaidman et al., 2024, Journal of Neuromuscular Diseases	04/2024	• In 85 treated patients, 96% had TEAEs and 86% had treatment-related AEs; vomiting was most frequent (~50–61%) • Acute liver injury occurred in 31/85 (36%); myocarditis and immune-mediated myositis each ~1/85 (~1%) (zaidman2024managementofselect pages 1-3, zaidman2024managementofselect pages 7-8, zaidman2024managementofselect pages 8-11)	https://doi.org/10.3233/jnd-230185	Delphi consensus / safety management paper
Regulatory / trial guidance	McDonald et al., 2024, Journal of Neuromuscular Diseases	02/2024	• Birth prevalence summarized as ~1 in 3,500–6,000 males • Guidance emphasizes surrogate-endpoint approvals, post-marketing placebo-controlled trials, and development across the full dystrophinopathy spectrum (mcdonald2024draftguidancefor pages 4-5)	https://doi.org/10.3233/jnd-230219	FDA/community guidance paper
Treatment—AAV gene therapy	D'Ambrosio & Mendell, 2023, Neurotherapeutics	10/2023	• Reviews delandistrogene moxeparvovec/SRP-9001 programs with >80 treated boys in later development • Reports protocol corticosteroids 1 mg/kg/day starting 24 h pre-infusion and key AEs including vomiting, transaminase/GGT elevations, thrombocytopenia, and immune-mediated myositis/myocarditis in 2 patients with large deletions (dambrosio2023evolvingtherapeuticoptions pages 8-9)	https://doi.org/10.1007/s13311-023-01423-y	Therapeutic review / clinical development overview

Table: This table summarizes the main recent studies and guidelines used as evidence in the Duchenne muscular dystrophy report, spanning epidemiology, natural history, respiratory care, and emerging therapies. It is useful for quickly locating the most relevant quantitative findings, publication dates, and evidence types.

1. Disease information

1.1 Definition and overview

DMD is the most common and most severe dystrophinopathy, resulting from DMD gene mutations that reduce dystrophin or impair its function, rendering muscle cell membranes vulnerable and driving progressive muscle degeneration, inflammation, and fibrosis (mcdonald2024draftguidancefor pages 4-5). Dystrophin is a cytoskeletal protein required for myofiber strength/stability and linkage of the cytoskeleton to the dystrophin‑associated protein complex (DAPC) (zhao2024comprehensiveanalysisof pages 1-2, krishna2024molecularandbiochemical pages 1-2). Clinically, DMD typically begins in early childhood with delayed motor milestones and progressive proximal weakness, then progresses to loss of ambulation and ultimately respiratory and cardiac failure (zhao2024comprehensiveanalysisof pages 1-2, mcdonald2024draftguidancefor pages 4-5).

1.2 Key identifiers and ontologies (availability in retrieved evidence)

The requested cross‑ontology identifiers (OMIM, Orphanet, MeSH, ICD‑11, MONDO) were not directly contained in the retrieved full‑text evidence snippets used for this report; therefore they cannot be asserted with tool‑verifiable citations here.

ICD‑10 (administrative data use): In German claims analyses, ICD‑10 code G71.0 (“muscular dystrophy”) is commonly used as an initial filter, but it is non‑specific and includes multiple muscular dystrophies beyond DMD; studies therefore require additional algorithmic criteria (e.g., glucocorticoid use in childhood, early wheelchair use, cardiomyopathy/heart medication, ventilation) to improve DMD specificity (diesing2025epidemiologydiseaseburden pages 2-4).

1.3 Synonyms / alternative names

Within the retrieved sources, DMD is frequently discussed under the umbrella term “dystrophinopathies” (including Duchenne muscular dystrophy, Becker muscular dystrophy, and dystrophin‑associated dilated cardiomyopathy) (krishna2024molecularandbiochemical pages 1-2). Additional synonym lists (e.g., “Duchenne dystrophy,” “pseudohypertrophic muscular dystrophy”) were not explicitly enumerated in the retrieved evidence.

1.4 Evidence provenance (patient‑level vs aggregated)

The evidence base used here includes aggregated resources (consensus guidelines and regulatory guidance) (mcdonald2024draftguidancefor pages 4-5, childs2024developmentofrespiratory pages 1-2), patient registries (STRIDE ataluren registry) (mercuri2023safetyandeffectiveness pages 1-2), national mortality/registry linkages (Sweden) (wahlgren2024respiratorycomorbiditiesand pages 1-2), nationwide prevalence ascertainment from specialist centers (Italy) (capasso2024prevalenceofduchenne pages 1-2), and administrative claims/EHR‑derived cohorts (England; Germany) (morgan2024epidemiologyandhealthcare pages 1-2, diesing2025epidemiologydiseaseburden pages 2-4).

2. Etiology

2.1 Disease causal factors

Primary cause: Germline pathogenic variants in the DMD gene on the X chromosome causing absent/reduced dystrophin protein (zaidman2024managementofselect pages 1-3).

Inheritance: X‑linked recessive (explicitly described as “recessive X‑linked” in recent gene‑therapy safety literature) (zaidman2024managementofselect pages 1-3).

2.2 Genetic risk factors: variant spectrum and genotype correlations

A large 2024 Chinese dystrophinopathy cohort (n=2,097; DMD n=1,703) reported the following variant class distribution: exonic deletions 66.6%, exonic duplications 10.7%, nonsense variants 10.3%, splice‑site variants 4.5%, small deletions 3.5%, small insertions/duplications 1.8%, missense variants 0.9%, plus rare deep intronic and inversion variants (zhao2024comprehensiveanalysisof pages 1-2). In the same cohort, 55.3% of DMD patients were estimated to be eligible for exon‑skipping therapy overall (with 12.9% eligible for exon 51 skipping, 10% for exon 53 skipping, and 9.6% for exon 45 skipping) (zhao2024comprehensiveanalysisof pages 1-2).

Direct abstract quote (variant spectrum): “The spectrum of identified variants included exonic deletions (66.6%), exonic duplications (10.7%), nonsense variants (10.3%), splice-site variants (4.5%), small deletions (3.5%), small insertions/duplications (1.8%), and missense variants (0.9%).” (zhao2024comprehensiveanalysisof pages 1-2)

2.3 Modifier genes / protective genetic factors (current evidence limitations)

Recent evidence in this tool run does not provide a comprehensive modifier‑gene review. One 2024 systematic review of predictors of cardiac disease in DMD (identified during search but not extracted here in the evidence snippets) is referenced in the state; however, modifier gene details were not returned in the gathered evidence. Therefore, a modifier gene list cannot be asserted with citations from this run.

2.4 Environmental and lifestyle risk factors / protective factors

DMD is a monogenic disorder; no environmental causal factors were identified in the retrieved evidence. However, care guidelines and observational studies note clinical factors that can worsen respiratory risk (e.g., overweight/Cushingoid features, often steroid‑related) even when pulmonary testing appears stable (childs2024developmentofrespiratory pages 3-3). This represents risk for complications rather than disease causation.

2.5 Gene–environment interactions

No explicit gene–environment interaction studies were captured in the retrieved evidence.

3. Phenotypes (clinical presentation, progression, and HPO suggestions)

3.1 Core neuromuscular phenotype

Typical onset is before age 5 years, with progression to wheelchair dependence often by 10–12 years and death commonly from cardiac/respiratory failure between 20–40 years (zhao2024comprehensiveanalysisof pages 1-2). Without disease‑modifying therapy, loss of ambulation is commonly before age 13 (mcdonald2024draftguidancefor pages 4-5).

Suggested HPO terms (non‑exhaustive; not directly extracted from HPO in this run): - Progressive muscle weakness (HP:0003323) - Proximal muscle weakness (HP:0008997) - Delayed gross motor development (HP:0002194) - Loss of ambulation (HP:0002505)

3.2 Respiratory phenotype

DMD respiratory decline is primarily due to intercostal and diaphragmatic weakness and tends to become clinically apparent after loss of ambulation; inspiratory weakness leads to nocturnal hypoventilation/sleep‑disordered breathing, and expiratory weakness causes ineffective cough and secretion clearance (childs2024developmentofrespiratory pages 1-2).

A Swedish mortality cohort found respiratory comorbidity is common: 70.1% had ≥1 pneumonia (median age at first pneumonia 17.8 years), and 73.0% developed hypoventilation (median onset 18.1 years) (wahlgren2024respiratorycomorbiditiesand pages 1-2). Acute respiratory failure accounted for 63.3% of respiratory‑related deaths (wahlgren2024respiratorycomorbiditiesand pages 1-2).

Suggested HPO terms: - Hypoventilation (HP:0002791) - Sleep apnea / sleep-disordered breathing (e.g., HP:0010535) - Recurrent respiratory infections / pneumonia (HP:0006532 / HP:0002090)

3.3 Cardiac phenotype

Consensus regulatory guidance emphasizes cardiomyopathy as a prominent life‑limiting feature in DMD, and notes that heart disease is now a leading cause of death as respiratory management has improved (mcdonald2024draftguidancefor pages 4-5).

Suggested HPO terms: - Dilated cardiomyopathy (HP:0001644) - Left ventricular systolic dysfunction (HP:0032094)

3.4 Quality‑of‑life impact

Direct quantitative HRQoL instruments (e.g., EQ‑5D, PedsQL) were not extracted in the evidence snippets. Functional milestones and respiratory/cardiac complications documented in cohort studies imply substantial impacts on mobility, independence, and survival (mcdonald2024draftguidancefor pages 4-5, wahlgren2024respiratorycomorbiditiesand pages 1-2).

4. Genetic / molecular information

4.1 Causal gene

DMD (dystrophin) is the causal gene; dystrophin is described as a large protein linking the cytoskeleton to the dystrophin‑associated protein complex (DAPC), supporting membrane stability (krishna2024molecularandbiochemical pages 1-2).

4.2 Functional consequences

Loss of functional dystrophin causes muscle membrane instability and progressive skeletal/cardiac muscle atrophy (krishna2024molecularandbiochemical pages 1-2). Regulatory guidance further frames the downstream cascade as progressive degeneration with inflammation and fibrosis driven by membrane vulnerability (mcdonald2024draftguidancefor pages 4-5).

4.3 Variant types and testing approaches (high level)

Clinical molecular diagnosis commonly uses methods capable of detecting large deletions/duplications such as MLPA or array‑CGH, consistent with the high proportion of structural variation (krishna2024molecularandbiochemical pages 1-2, zhao2024comprehensiveanalysisof pages 1-2).

5. Environmental information

No infectious etiology or environmental cause is applicable for DMD in the retrieved evidence.

6. Mechanism / pathophysiology (with ontology suggestions)

6.1 Causal chain (current understanding)

1) Pathogenic DMD variant → dystrophin absent/reduced (zaidman2024managementofselect pages 1-3). 2) Loss of dystrophin/DAPC linkage → membrane vulnerability (mcdonald2024draftguidancefor pages 4-5, krishna2024molecularandbiochemical pages 1-2). 3) Repeated contraction injury → myofiber degeneration → inflammation and fibrosis (mcdonald2024draftguidancefor pages 4-5). 4) Organ-level failure: progressive skeletal muscle weakness, respiratory muscle weakness (nocturnal hypoventilation, cough failure), and cardiomyopathy leading to morbidity and premature mortality (mcdonald2024draftguidancefor pages 4-5, childs2024developmentofrespiratory pages 1-2, wahlgren2024respiratorycomorbiditiesand pages 1-2).

6.2 Pathways and cellular processes highlighted in retrieved sources

Inflammation and fibrosis are explicitly emphasized as downstream processes in regulatory guidance for dystrophinopathies (mcdonald2024draftguidancefor pages 4-5).
Mechanistic rationale for cardioprotective drugs includes angiotensin II‑mediated oxidative stress and fibrosis in cardiomyopathy (review evidence) (krishna2024molecularandbiochemical pages 23-25).

6.3 Ontology suggestions

GO biological process (examples): - Muscle cell differentiation / muscle adaptation - Inflammatory response - Extracellular matrix organization / fibrosis

Cell Ontology (CL) candidates: - Skeletal muscle cell / myofiber (CL:0000187) - Cardiomyocyte (CL:0000746)

UBERON anatomy: - Skeletal muscle organ (UBERON:0001134) - Heart (UBERON:0000948) - Diaphragm (UBERON:0001103)

(These ontology IDs are provided as plausible mappings; they were not directly looked up in this tool run and therefore are not citation-supported here.)

7. Anatomical structures affected

Primary tissues are skeletal muscle and cardiac muscle; respiratory insufficiency reflects involvement of diaphragm and intercostal muscles (childs2024developmentofrespiratory pages 1-2, mcdonald2024draftguidancefor pages 4-5). Multi‑organ involvement is also noted in gene‑therapy safety literature (zaidman2024managementofselect pages 1-3).

8. Temporal development (onset and progression)

Onset: typically before age 5 (zhao2024comprehensiveanalysisof pages 1-2).
Progression: wheelchair dependence often by 10–12 years (zhao2024comprehensiveanalysisof pages 1-2); respiratory decline becomes prominent after loss of ambulation, often in adolescence/adulthood (childs2024developmentofrespiratory pages 1-2).
Respiratory milestones: in Sweden, median onset of hypoventilation ~18.1 years and first pneumonia ~17.8 years (wahlgren2024respiratorycomorbiditiesand pages 1-2).

9. Inheritance and population

9.1 Epidemiology (recent estimates)

Estimates vary by ascertainment method and denominators: - Italy (nationwide survey; Jan 2021–Dec 2023 follow‑up): period prevalence 1.65/100,000 overall and 3.4/100,000 males (capasso2024prevalenceofduchenne pages 1-2). Cohort characteristics included 43% ambulant and 57% non‑ambulant (capasso2024prevalenceofduchenne pages 1-2). - England (CPRD Aurum; 2020 point prevalence): 3.23/100,000 (95% CI 2.82–3.63) (morgan2024epidemiologyandhealthcare pages 1-2). - Global birth prevalence range (regulatory guidance): approximately 1 in 3,500–6,000 males (mcdonald2024draftguidancefor pages 4-5). - China (cohort context statement): worldwide live male birth prevalence cited as ~1 in 3,600–6,300; China estimate cited as 1 in 4,560 (zhao2024comprehensiveanalysisof pages 1-2).

9.2 Healthcare utilization and cost (real‑world)

In England claims data, DMD was associated with much higher healthcare utilization than matched controls: primary care contacts IRR 3.19, inpatient admissions IRR 9.24, outpatient appointments IRR 11.44, and adjusted cost ratio 9.33 (morgan2024epidemiologyandhealthcare pages 1-2). Stage‑linked mean annual costs were reported as £2,816 (ambulatory), £5,700 (non‑ambulatory without ventilation), and £7,634 (non‑ambulatory with ventilation) (morgan2024epidemiologyandhealthcare pages 1-2).

9.3 Sex ratio

As an X‑linked recessive condition, DMD predominantly affects males; multiple cohorts in this report are male-only by design (wahlgren2024respiratorycomorbiditiesand pages 1-2, zhao2024comprehensiveanalysisof pages 1-2).

10. Diagnostics

10.1 Core diagnostic approach (from retrieved sources)

Molecular testing approaches capable of detecting deletions/duplications are emphasized (MLPA, array‑CGH) (krishna2024molecularandbiochemical pages 1-2). Large cohort data show deletions/duplications constitute the majority of pathogenic variation, supporting this strategy (zhao2024comprehensiveanalysisof pages 1-2).

10.2 Respiratory monitoring as part of longitudinal assessment (2024 UK guideline)

The 2024 UK BTS‑endorsed consensus guideline recommends routine respiratory surveillance beginning as soon as feasible after diagnosis and typically performed routinely by age 6 (childs2024developmentofrespiratory pages 2-3). Suggested monitoring frequency is every 6–12 months while ambulatory and every 6 months when non‑ambulatory (childs2024developmentofrespiratory pages 3-3). Minimum assessment includes targeted history, FVC, and peak cough flow (childs2024developmentofrespiratory pages 3-3).

Key threshold‑linked recommendations include: - Patients with FVC ≤50% predicted “should remain under respiratory review and should not be discharged from respiratory clinics” (childs2024developmentofrespiratory pages 6-7). - The guideline cautions that “daytime saturations should not be relied on to diagnose or rule out ventilatory failure” (childs2024developmentofrespiratory pages 6-7).

In emergency/acute settings, the guideline excerpt advises considering NIV with hypoxemia (<95%), hypercapnia (>45 mm Hg / 6 kPa), or clinical fatigue, and warns against giving oxygen alone without checking for hypercapnia (childs2024developmentofrespiratory pages 8-8).

10.3 Early diagnosis / screening

Newborn screening and formal early‑diagnosis pathways were not captured in full within the retrieved evidence snippets. One preprint model notes that affected status can be determined at birth and references newborn screening pilots in discussion, but it does not provide implementable screening protocols in the extracted text (kingsmore2024mathematicalmodelingof pages 8-10).

11. Outcomes / prognosis

11.1 Survival and causes of death (recent cohort data)

In Sweden (males born/deceased 1970–2019; n=129), median lifespan was 24.3 years, with pneumonia and hypoventilation common and acute respiratory failure responsible for 63.3% of respiratory‑related causes of death (wahlgren2024respiratorycomorbiditiesand pages 1-2). The authors note that assisted ventilation and combined respiratory/cardiac management have been associated with improved life expectancy in modern eras (wahlgren2024respiratorycomorbiditiesand pages 1-2).

11.2 Disease milestones and supportive technology utilization (Italy)

In the Italian nationwide survey, ~73% had no ventilatory support, 9% had NIV >12 hours, and 1.4% had tracheostomy at last assessment; median age at any respiratory support was 18 years (capasso2024prevalenceofduchenne pages 5-8).

12. Treatment

12.1 Standard of care / supportive care (respiratory)

The 2024 UK guideline emphasizes multidisciplinary respiratory care with ongoing surveillance and early recognition of sleep‑disordered breathing, cough weakness, and infection risk; it recommends prompt referral to specialist respiratory physiotherapy and anticipatory prescription of assisted cough devices (MI‑E settings individualized by experts) (childs2024developmentofrespiratory pages 6-7, childs2024developmentofrespiratory pages 8-9).

MAXO suggestions (not directly mapped in evidence): noninvasive ventilation; mechanically assisted cough; respiratory physiotherapy.

12.2 Glucocorticoids

Regulatory guidance and cohort data support glucocorticoids as disease‑modifying therapy that shifts milestone timing but carries important adverse effects (weight gain, growth inhibition, bone fragility/fractures, diabetes risk, behavioral changes, Cushingoid features, puberty effects, cataracts) (mcdonald2024draftguidancefor pages 4-5).

In the 2024 Chinese cohort, glucocorticoid treatment was associated with a median 2.5‑year delay in loss of ambulation (zhao2024comprehensiveanalysisof pages 1-2).

12.3 Variant‑targeted therapies

12.3.1 Stop‑codon readthrough (ataluren) in nonsense‑mutation DMD (real‑world)

The STRIDE registry (NCT02369731) reported, as of Jan 31, 2022, 307 patients enrolled from 14 countries with mean ages at first symptoms 2.9 years and genetic diagnosis 4.5 years and mean ataluren exposure 1671 days (mercuri2023safetyandeffectiveness pages 1-2). In propensity‑matched comparisons vs CINRG natural history, ataluren + standard of care delayed: - Loss of ambulation by ~4 years (median 17.0 vs 13.0 years; p<0.0001) (mercuri2023safetyandeffectiveness pages 10-11, mercuri2023safetyandeffectiveness pages 11-13) - Decline to FVC <60% by 1.8 years and FVC <50% by 2.3 years (mercuri2023safetyandeffectiveness pages 1-2, mercuri2023safetyandeffectiveness pages 10-11)

Direct abstract quote (effectiveness): “Kaplan–Meier analyses demonstrated that ataluren plus SoC significantly delayed age at loss of ambulation by 4 years … and age at decline to %-predicted forced vital capacity of <60% and <50% by 1.8 years … and 2.3 years … compared with SoC alone.” (mercuri2023safetyandeffectiveness pages 1-2)

Safety findings included that ataluren was well tolerated in the registry with no deaths to cutoff and relatively low proportions of TEAEs judged related to ataluren (3.2% of TEAEs related) (mercuri2023safetyandeffectiveness pages 6-7).

12.3.2 Exon‑skipping antisense oligonucleotides (ASOs)

A 2024 mechanistic review summarizes exon‑skipping PMO therapies (eteplirsen exon 51; golodirsen exon 53; casimersen exon 45) as producing internally shortened dystrophin by restoring the reading frame, with limitations including variable dystrophin restoration and, for golodirsen, historical FDA concerns about renal toxicity (krishna2024molecularandbiochemical pages 5-7).

Real‑world implementation gaps are suggested by cohort/claims contexts rather than head‑to‑head effectiveness in the retrieved evidence: in China, although >55% were exon‑skipping eligible, the report emphasizes gaps in routine monitoring and treatment uptake (zhao2024comprehensiveanalysisof pages 1-2).

12.4 AAV micro‑dystrophin gene transfer: delandistrogene moxeparvovec (SRP‑9001)

12.4.1 Indication and real‑world implementation considerations

A 2024 Delphi consensus paper states that delandistrogene moxeparvovec is indicated for ambulatory pediatric patients aged 4–5 years with an indicated DMD mutation (zaidman2024managementofselect pages 1-3).

12.4.2 Safety signals and management (2024 consensus)

The Delphi panel focused on treatment‑related adverse events (TRAEs) including vomiting, acute liver injury (ALI), myocarditis, and immune‑mediated myositis (IMM) and recommended baseline lab assessments (CMP including AST/ALT/bilirubin; troponin; complement; CBC; coagulation; cystatin C, etc.) and post‑infusion serial monitoring (weekly liver enzymes for ~3 months; weekly troponin during first month; weekly platelets for first 2 weeks) (zaidman2024managementofselect pages 3-4).

In clinical development safety data summarized by the consensus paper (n=85), vomiting was the most frequent TRAE (reported ~50–61%); ALI occurred in 31/85 (36%) typically 4–8 weeks post infusion; myocarditis and IMM were each ~1/85 (~1%) (zaidman2024managementofselect pages 8-11). Management principles included prompt escalation of corticosteroids for immune‑mediated events and specialist consultation; refractory cases may require IV methylprednisolone, IVIg, or plasmapheresis (zaidman2024managementofselect pages 8-11, zaidman2024managementofselect pages 6-7).

A 2023 therapeutic review provides additional clinical development context, noting immune‑mediated myositis with myocarditis in two patients with large exon deletions in early programs, managed with intensified immunosuppression (prednisone, plasmapheresis, tacrolimus), and those mutation classes were subsequently excluded (dambrosio2023evolvingtherapeuticoptions pages 8-9).

13. Prevention

Primary prevention is not applicable because DMD is inherited; prevention focuses on genetic counseling and family planning. No prevention guidelines or carrier screening/newborn screening program details were captured in the retrieved evidence snippets.

14. Other species / natural disease

Naturally occurring animal disease and veterinary relevance were not captured in the retrieved evidence snippets in this run.

15. Model organisms

This tool run did not extract specific model‑organism descriptions (e.g., mdx mouse, dystrophic dogs) beyond general mentions in therapeutic reviews that preclinical efficacy has been demonstrated in mdx mice and dystrophic dogs for micro‑dystrophin approaches (krishna2024molecularandbiochemical pages 5-7). A structured model‑organism section would require additional targeted retrieval.

Expert opinions and authoritative analysis (as captured in recent guidance)

The 2024 FDA/community draft guidance emphasizes patient‑focused drug development, the role of dystrophin as a biomarker, MRI for progression assessment, cardiomyopathy prominence, and the evolving field of gene therapy (mcdonald2024draftguidancefor pages 4-5). It also explicitly notes that several exon‑skipping drugs were approved using surrogate endpoints and encourages completion of post‑marketing placebo‑controlled trials (mcdonald2024draftguidancefor pages 4-5).
The 2024 UK BTS‑endorsed respiratory guideline highlights gaps and inconsistencies in care provision and provides consensus flow‑based recommendations for routine and emergency respiratory management (childs2024developmentofrespiratory pages 1-2).

Data gaps and limitations (important for knowledge base curation)

1) Ontology identifiers (MONDO/OMIM/Orphanet/MeSH/ICD‑11) were not available in the retrieved evidence snippets; they should be populated from dedicated ontology sources (OMIM/Orphanet/MONDO) in a subsequent retrieval step. 2) Modifier genes, epigenetics, and multi‑omics were not comprehensively captured in extracted evidence in this run. 3) Newborn screening and carrier screening details were not retrieved with implementable specificity. 4) Model organism and natural animal disease evidence is incomplete.

URLs and publication dates (where available)

URLs and month/year publication dates for the major cited sources are included in the table artifact embedded above (artifact-00) and in citations throughout the text.

References

(capasso2024prevalenceofduchenne pages 1-2): Anna Capasso, Gianpaolo Cicala, Martina Ricci, Marika Pane, Adele D’Amico, Claudio Bruno, Valeria Ada Sansone, Sonia Messina, Luca Bello, Elena Pegoraro, Maria Grazia D’Angelo, Riccardo Masson, Angela Berardinelli, Antonella Pini, Federica Ricci, Tiziana Enrica Mongini, Michela Coccia, Vincenzo Nigro, Antonio Trabacca, Massimiliano Filosto, Giacomo Comi, Francesca Magri, Andrea Barp, Roberta Battini, Stefano Carlo Previtali, Maria Lucia Valentino, Eleonora Diella, Claudia Dosi, Lucia Ruggiero, Gabriele Siciliano, Giulia Ricci, Michela Catteruccia, Chiara Arpaia, Giorgia Coratti, Giulia Norcia, Silvia Bonanno, Lorenzo Verriello, Caterina Agosto, Antonio Varone, Alessandra Ferlini, Maria Antonietta Maioli, Claudia Brogna, Sabrina Siliquini, Irene Bruno, Chiara Panicucci, Cosimo Allegra, Emilio Albamonte, Eugenio Mercuri, Concetta Palermo, Daniela Leone, Costanza Cutrona, Laura Antonaci, Simona Lucibello, Elisabetta Ferraroli, Maria Carmela Pera, Giulia Stanca, Bianca Buchignani, Lorenzo Maggi, Enrico Bertini, Giacomo de Luca, Marina Pedemonte, Federica Trucco, Melania Giannotta, Riccardo Zanin, Maria Sframeli, Alessandra Nastasi, Simona Damioli, Alice Gardani, Riccardo Zuccarino, Alberto A. Zambon, Amanda Ferrero, and Giorgia Bruno. Prevalence of duchenne muscular dystrophy in italy: a nationwide survey. European journal of pediatrics, 184 1:86, Dec 2024. URL: https://doi.org/10.1007/s00431-024-05903-x, doi:10.1007/s00431-024-05903-x. This article has 4 citations and is from a peer-reviewed journal.
(morgan2024epidemiologyandhealthcare pages 1-2): Christopher Llewellyn Morgan, Josie Godfrey, Fleur Chandler, Emily Reuben, and Craig J. Currie. Epidemiology and healthcare resource utilisation associated with duchenne muscular dystrophy. Journal of Rare Diseases, Aug 2024. URL: https://doi.org/10.1007/s44162-024-00044-z, doi:10.1007/s44162-024-00044-z. This article has 4 citations.
(wahlgren2024respiratorycomorbiditiesand pages 1-2): Lisa Wahlgren, Anna-Karin Kroksmark, Anders Lindblad, Mar Tulinius, and Kalliopi Sofou. Respiratory comorbidities and treatments in duchenne muscular dystrophy: impact on life expectancy and causes of death. Journal of Neurology, 271:4300-4309, Apr 2024. URL: https://doi.org/10.1007/s00415-024-12372-7, doi:10.1007/s00415-024-12372-7. This article has 26 citations and is from a domain leading peer-reviewed journal.
(mercuri2023safetyandeffectiveness pages 1-2): Eugenio Mercuri, Andrés Nascimento Osorio, Francesco Muntoni, Filippo Buccella, Isabelle Desguerre, Janbernd Kirschner, Már Tulinius, Maria Bernadete Dutra de Resende, Lauren P. Morgenroth, Heather Gordish-Dressman, Shelley Johnson, Allan Kristensen, Christian Werner, Panayiota Trifillis, Erik K. Henricson, and Craig M. McDonald. Safety and effectiveness of ataluren in patients with nonsense mutation dmd in the stride registry compared with the cinrg duchenne natural history study (2015–2022): 2022 interim analysis. Journal of Neurology, 270:3896-3913, Apr 2023. URL: https://doi.org/10.1007/s00415-023-11687-1, doi:10.1007/s00415-023-11687-1. This article has 57 citations and is from a domain leading peer-reviewed journal.
(zaidman2024managementofselect pages 8-11): Craig M. Zaidman, Natalie L. Goedeker, Amal A. Aqul, Russell J. Butterfield, Anne M. Connolly, Ronald G. Crystal, Kara E. Godwin, Kan N. Hor, Katherine D. Mathews, Crystal M. Proud, Elizabeth Kula Smyth, Aravindhan Veerapandiyan, Paul B. Watkins, and Jerry R. Mendell. Management of select adverse events following delandistrogene moxeparvovec gene therapy for patients with duchenne muscular dystrophy. Journal of Neuromuscular Diseases, 11:687-699, Apr 2024. URL: https://doi.org/10.3233/jnd-230185, doi:10.3233/jnd-230185. This article has 22 citations and is from a peer-reviewed journal.
(capasso2024prevalenceofduchenne pages 5-8): Anna Capasso, Gianpaolo Cicala, Martina Ricci, Marika Pane, Adele D’Amico, Claudio Bruno, Valeria Ada Sansone, Sonia Messina, Luca Bello, Elena Pegoraro, Maria Grazia D’Angelo, Riccardo Masson, Angela Berardinelli, Antonella Pini, Federica Ricci, Tiziana Enrica Mongini, Michela Coccia, Vincenzo Nigro, Antonio Trabacca, Massimiliano Filosto, Giacomo Comi, Francesca Magri, Andrea Barp, Roberta Battini, Stefano Carlo Previtali, Maria Lucia Valentino, Eleonora Diella, Claudia Dosi, Lucia Ruggiero, Gabriele Siciliano, Giulia Ricci, Michela Catteruccia, Chiara Arpaia, Giorgia Coratti, Giulia Norcia, Silvia Bonanno, Lorenzo Verriello, Caterina Agosto, Antonio Varone, Alessandra Ferlini, Maria Antonietta Maioli, Claudia Brogna, Sabrina Siliquini, Irene Bruno, Chiara Panicucci, Cosimo Allegra, Emilio Albamonte, Eugenio Mercuri, Concetta Palermo, Daniela Leone, Costanza Cutrona, Laura Antonaci, Simona Lucibello, Elisabetta Ferraroli, Maria Carmela Pera, Giulia Stanca, Bianca Buchignani, Lorenzo Maggi, Enrico Bertini, Giacomo de Luca, Marina Pedemonte, Federica Trucco, Melania Giannotta, Riccardo Zanin, Maria Sframeli, Alessandra Nastasi, Simona Damioli, Alice Gardani, Riccardo Zuccarino, Alberto A. Zambon, Amanda Ferrero, and Giorgia Bruno. Prevalence of duchenne muscular dystrophy in italy: a nationwide survey. European journal of pediatrics, 184 1:86, Dec 2024. URL: https://doi.org/10.1007/s00431-024-05903-x, doi:10.1007/s00431-024-05903-x. This article has 4 citations and is from a peer-reviewed journal.
(zhao2024comprehensiveanalysisof pages 1-2): Lei Zhao, Yiyun Shi, Chaoping Hu, Shuizhen Zhou, Hui Li, Lifeng Zhang, Chuang Qian, Yiyao Zhou, Yi Wang, and Xihua Li. Comprehensive analysis of 2097 patients with dystrophinopathy based on a database from 2011 to 2021. Orphanet Journal of Rare Diseases, Aug 2024. URL: https://doi.org/10.1186/s13023-024-03217-7, doi:10.1186/s13023-024-03217-7. This article has 4 citations and is from a peer-reviewed journal.
(childs2024developmentofrespiratory pages 6-7): Anne-Marie Childs, Catherine Turner, Ronan Astin, Stephen Bianchi, John Bourke, Vicki Cunningham, Lisa Edel, Christopher Edwards, Phillippa Farrant, Jane Heraghty, Meredith James, Charlotte Massey, Ben Messer, Jassi Michel Sodhi, Patrick Brian Murphy, Marianela Schiava, Ajit Thomas, Federica Trucco, and Michela Guglieri. Development of respiratory care guidelines for duchenne muscular dystrophy in the uk: key recommendations for clinical practice. Thorax, 79:476-485, Dec 2024. URL: https://doi.org/10.1136/thorax-2023-220811, doi:10.1136/thorax-2023-220811. This article has 24 citations and is from a domain leading peer-reviewed journal.
(childs2024developmentofrespiratory pages 3-3): Anne-Marie Childs, Catherine Turner, Ronan Astin, Stephen Bianchi, John Bourke, Vicki Cunningham, Lisa Edel, Christopher Edwards, Phillippa Farrant, Jane Heraghty, Meredith James, Charlotte Massey, Ben Messer, Jassi Michel Sodhi, Patrick Brian Murphy, Marianela Schiava, Ajit Thomas, Federica Trucco, and Michela Guglieri. Development of respiratory care guidelines for duchenne muscular dystrophy in the uk: key recommendations for clinical practice. Thorax, 79:476-485, Dec 2024. URL: https://doi.org/10.1136/thorax-2023-220811, doi:10.1136/thorax-2023-220811. This article has 24 citations and is from a domain leading peer-reviewed journal.
(childs2024developmentofrespiratory pages 1-2): Anne-Marie Childs, Catherine Turner, Ronan Astin, Stephen Bianchi, John Bourke, Vicki Cunningham, Lisa Edel, Christopher Edwards, Phillippa Farrant, Jane Heraghty, Meredith James, Charlotte Massey, Ben Messer, Jassi Michel Sodhi, Patrick Brian Murphy, Marianela Schiava, Ajit Thomas, Federica Trucco, and Michela Guglieri. Development of respiratory care guidelines for duchenne muscular dystrophy in the uk: key recommendations for clinical practice. Thorax, 79:476-485, Dec 2024. URL: https://doi.org/10.1136/thorax-2023-220811, doi:10.1136/thorax-2023-220811. This article has 24 citations and is from a domain leading peer-reviewed journal.
(mercuri2023safetyandeffectiveness pages 10-11): Eugenio Mercuri, Andrés Nascimento Osorio, Francesco Muntoni, Filippo Buccella, Isabelle Desguerre, Janbernd Kirschner, Már Tulinius, Maria Bernadete Dutra de Resende, Lauren P. Morgenroth, Heather Gordish-Dressman, Shelley Johnson, Allan Kristensen, Christian Werner, Panayiota Trifillis, Erik K. Henricson, and Craig M. McDonald. Safety and effectiveness of ataluren in patients with nonsense mutation dmd in the stride registry compared with the cinrg duchenne natural history study (2015–2022): 2022 interim analysis. Journal of Neurology, 270:3896-3913, Apr 2023. URL: https://doi.org/10.1007/s00415-023-11687-1, doi:10.1007/s00415-023-11687-1. This article has 57 citations and is from a domain leading peer-reviewed journal.
(mercuri2023safetyandeffectiveness pages 6-7): Eugenio Mercuri, Andrés Nascimento Osorio, Francesco Muntoni, Filippo Buccella, Isabelle Desguerre, Janbernd Kirschner, Már Tulinius, Maria Bernadete Dutra de Resende, Lauren P. Morgenroth, Heather Gordish-Dressman, Shelley Johnson, Allan Kristensen, Christian Werner, Panayiota Trifillis, Erik K. Henricson, and Craig M. McDonald. Safety and effectiveness of ataluren in patients with nonsense mutation dmd in the stride registry compared with the cinrg duchenne natural history study (2015–2022): 2022 interim analysis. Journal of Neurology, 270:3896-3913, Apr 2023. URL: https://doi.org/10.1007/s00415-023-11687-1, doi:10.1007/s00415-023-11687-1. This article has 57 citations and is from a domain leading peer-reviewed journal.
(zaidman2024managementofselect pages 1-3): Craig M. Zaidman, Natalie L. Goedeker, Amal A. Aqul, Russell J. Butterfield, Anne M. Connolly, Ronald G. Crystal, Kara E. Godwin, Kan N. Hor, Katherine D. Mathews, Crystal M. Proud, Elizabeth Kula Smyth, Aravindhan Veerapandiyan, Paul B. Watkins, and Jerry R. Mendell. Management of select adverse events following delandistrogene moxeparvovec gene therapy for patients with duchenne muscular dystrophy. Journal of Neuromuscular Diseases, 11:687-699, Apr 2024. URL: https://doi.org/10.3233/jnd-230185, doi:10.3233/jnd-230185. This article has 22 citations and is from a peer-reviewed journal.
(zaidman2024managementofselect pages 7-8): Craig M. Zaidman, Natalie L. Goedeker, Amal A. Aqul, Russell J. Butterfield, Anne M. Connolly, Ronald G. Crystal, Kara E. Godwin, Kan N. Hor, Katherine D. Mathews, Crystal M. Proud, Elizabeth Kula Smyth, Aravindhan Veerapandiyan, Paul B. Watkins, and Jerry R. Mendell. Management of select adverse events following delandistrogene moxeparvovec gene therapy for patients with duchenne muscular dystrophy. Journal of Neuromuscular Diseases, 11:687-699, Apr 2024. URL: https://doi.org/10.3233/jnd-230185, doi:10.3233/jnd-230185. This article has 22 citations and is from a peer-reviewed journal.
(mcdonald2024draftguidancefor pages 4-5): Craig M McDonald, Eric Camino, Rafael Escandon, Richard S. Finkel, Ryan Fischer, Kevin M. Flanigan, Pat Furlong, Rose Juhasz, Ann S Martin, Chet Villa, and H. L. Sweeney. Draft guidance for industry duchenne muscular dystrophy, becker muscular dystrophy, and related dystrophinopathies – developing potential treatments for the entire spectrum of disease. Journal of Neuromuscular Diseases, 11:499-523, Feb 2024. URL: https://doi.org/10.3233/jnd-230219, doi:10.3233/jnd-230219. This article has 14 citations and is from a peer-reviewed journal.
(dambrosio2023evolvingtherapeuticoptions pages 8-9): Eleonora S. D'Ambrosio and Jerry R. Mendell. Evolving therapeutic options for the treatment of duchenne muscular dystrophy. Neurotherapeutics, 20:1669-1681, Oct 2023. URL: https://doi.org/10.1007/s13311-023-01423-y, doi:10.1007/s13311-023-01423-y. This article has 38 citations and is from a peer-reviewed journal.
(krishna2024molecularandbiochemical pages 1-2): Lakshmi Krishna, Akila Prashant, Yogish H. Kumar, Shasthara Paneyala, Siddaramappa J. Patil, Shobha Chikkavaddaragudi Ramachandra, and Prashant Vishwanath. Molecular and biochemical therapeutic strategies for duchenne muscular dystrophy. Neurology International, 16:731-760, Jul 2024. URL: https://doi.org/10.3390/neurolint16040055, doi:10.3390/neurolint16040055. This article has 17 citations.
(diesing2025epidemiologydiseaseburden pages 2-4): J. Diesing, Jan Kirschner, A. Pechmann, Jörg König, Leonie Kunk, Tarcyane Barata Garcia, C. Schwedhelm, Carsta Militzer-Horstmann, Ivonne Hänsel, and A. Kisser. Epidemiology, disease burden and costs of duchenne muscular dystrophy in germany: an observational, retrospective health claims data analysis. Orphanet Journal of Rare Diseases, Aug 2025. URL: https://doi.org/10.1186/s13023-025-03906-x, doi:10.1186/s13023-025-03906-x. This article has 4 citations and is from a peer-reviewed journal.
(krishna2024molecularandbiochemical pages 23-25): Lakshmi Krishna, Akila Prashant, Yogish H. Kumar, Shasthara Paneyala, Siddaramappa J. Patil, Shobha Chikkavaddaragudi Ramachandra, and Prashant Vishwanath. Molecular and biochemical therapeutic strategies for duchenne muscular dystrophy. Neurology International, 16:731-760, Jul 2024. URL: https://doi.org/10.3390/neurolint16040055, doi:10.3390/neurolint16040055. This article has 17 citations.
(childs2024developmentofrespiratory pages 2-3): Anne-Marie Childs, Catherine Turner, Ronan Astin, Stephen Bianchi, John Bourke, Vicki Cunningham, Lisa Edel, Christopher Edwards, Phillippa Farrant, Jane Heraghty, Meredith James, Charlotte Massey, Ben Messer, Jassi Michel Sodhi, Patrick Brian Murphy, Marianela Schiava, Ajit Thomas, Federica Trucco, and Michela Guglieri. Development of respiratory care guidelines for duchenne muscular dystrophy in the uk: key recommendations for clinical practice. Thorax, 79:476-485, Dec 2024. URL: https://doi.org/10.1136/thorax-2023-220811, doi:10.1136/thorax-2023-220811. This article has 24 citations and is from a domain leading peer-reviewed journal.
(childs2024developmentofrespiratory pages 8-8): Anne-Marie Childs, Catherine Turner, Ronan Astin, Stephen Bianchi, John Bourke, Vicki Cunningham, Lisa Edel, Christopher Edwards, Phillippa Farrant, Jane Heraghty, Meredith James, Charlotte Massey, Ben Messer, Jassi Michel Sodhi, Patrick Brian Murphy, Marianela Schiava, Ajit Thomas, Federica Trucco, and Michela Guglieri. Development of respiratory care guidelines for duchenne muscular dystrophy in the uk: key recommendations for clinical practice. Thorax, 79:476-485, Dec 2024. URL: https://doi.org/10.1136/thorax-2023-220811, doi:10.1136/thorax-2023-220811. This article has 24 citations and is from a domain leading peer-reviewed journal.
(kingsmore2024mathematicalmodelingof pages 8-10): Stephen Kingsmore, Dominic Baun, Laura Tobin, Hung Nguyen, Madison Arenchild, Edwin Juarez, elizabeth kiernan, Daniel Lesser, Emily Wong, Daria Prilutsky, Neta Zach, Steve Han, Dorothee Diogo, Sandor Szalma, and Chamindra Laverty. Mathematical modeling of the progression of duchenne muscular dystrophy in san diego in an era of allele specific oligonucleotide therapy. Apr 2024. URL: https://doi.org/10.21203/rs.3.rs-4049883/v1, doi:10.21203/rs.3.rs-4049883/v1.
(childs2024developmentofrespiratory pages 8-9): Anne-Marie Childs, Catherine Turner, Ronan Astin, Stephen Bianchi, John Bourke, Vicki Cunningham, Lisa Edel, Christopher Edwards, Phillippa Farrant, Jane Heraghty, Meredith James, Charlotte Massey, Ben Messer, Jassi Michel Sodhi, Patrick Brian Murphy, Marianela Schiava, Ajit Thomas, Federica Trucco, and Michela Guglieri. Development of respiratory care guidelines for duchenne muscular dystrophy in the uk: key recommendations for clinical practice. Thorax, 79:476-485, Dec 2024. URL: https://doi.org/10.1136/thorax-2023-220811, doi:10.1136/thorax-2023-220811. This article has 24 citations and is from a domain leading peer-reviewed journal.
(mercuri2023safetyandeffectiveness pages 11-13): Eugenio Mercuri, Andrés Nascimento Osorio, Francesco Muntoni, Filippo Buccella, Isabelle Desguerre, Janbernd Kirschner, Már Tulinius, Maria Bernadete Dutra de Resende, Lauren P. Morgenroth, Heather Gordish-Dressman, Shelley Johnson, Allan Kristensen, Christian Werner, Panayiota Trifillis, Erik K. Henricson, and Craig M. McDonald. Safety and effectiveness of ataluren in patients with nonsense mutation dmd in the stride registry compared with the cinrg duchenne natural history study (2015–2022): 2022 interim analysis. Journal of Neurology, 270:3896-3913, Apr 2023. URL: https://doi.org/10.1007/s00415-023-11687-1, doi:10.1007/s00415-023-11687-1. This article has 57 citations and is from a domain leading peer-reviewed journal.
(krishna2024molecularandbiochemical pages 5-7): Lakshmi Krishna, Akila Prashant, Yogish H. Kumar, Shasthara Paneyala, Siddaramappa J. Patil, Shobha Chikkavaddaragudi Ramachandra, and Prashant Vishwanath. Molecular and biochemical therapeutic strategies for duchenne muscular dystrophy. Neurology International, 16:731-760, Jul 2024. URL: https://doi.org/10.3390/neurolint16040055, doi:10.3390/neurolint16040055. This article has 17 citations.
(zaidman2024managementofselect pages 3-4): Craig M. Zaidman, Natalie L. Goedeker, Amal A. Aqul, Russell J. Butterfield, Anne M. Connolly, Ronald G. Crystal, Kara E. Godwin, Kan N. Hor, Katherine D. Mathews, Crystal M. Proud, Elizabeth Kula Smyth, Aravindhan Veerapandiyan, Paul B. Watkins, and Jerry R. Mendell. Management of select adverse events following delandistrogene moxeparvovec gene therapy for patients with duchenne muscular dystrophy. Journal of Neuromuscular Diseases, 11:687-699, Apr 2024. URL: https://doi.org/10.3233/jnd-230185, doi:10.3233/jnd-230185. This article has 22 citations and is from a peer-reviewed journal.
(zaidman2024managementofselect pages 6-7): Craig M. Zaidman, Natalie L. Goedeker, Amal A. Aqul, Russell J. Butterfield, Anne M. Connolly, Ronald G. Crystal, Kara E. Godwin, Kan N. Hor, Katherine D. Mathews, Crystal M. Proud, Elizabeth Kula Smyth, Aravindhan Veerapandiyan, Paul B. Watkins, and Jerry R. Mendell. Management of select adverse events following delandistrogene moxeparvovec gene therapy for patients with duchenne muscular dystrophy. Journal of Neuromuscular Diseases, 11:687-699, Apr 2024. URL: https://doi.org/10.3233/jnd-230185, doi:10.3233/jnd-230185. This article has 22 citations and is from a peer-reviewed journal.

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Mappings

Inheritance

Subtypes

Mechanistic Hypotheses

Discussions and Knowledge Gaps

Pathophysiology

Pathograph

Phenotypes

Genetic Associations

Treatments

Biochemical Markers

Clinical Trials

Source YAML

References & Deep Research

References

Deep Research

Disease Characteristics Research Template

Target Disease

Research Objectives

1. Disease Information

2. Etiology

3. Phenotypes

4. Genetic/Molecular Information

5. Environmental Information

6. Mechanism / Pathophysiology

7. Anatomical Structures Affected

8. Temporal Development

9. Inheritance and Population

10. Diagnostics

11. Outcome/Prognosis

12. Treatment

13. Prevention

14. Other Species / Natural Disease

15. Model Organisms

Citation Requirements

Output Format

Duchenne Muscular Dystrophy (DMD): Disease Characteristics Research Report (2023–2025 evidence prioritized)

Executive summary

1. Disease information

1.1 Definition and overview

1.2 Key identifiers and ontologies (availability in retrieved evidence)

1.3 Synonyms / alternative names

1.4 Evidence provenance (patient‑level vs aggregated)

2. Etiology

2.1 Disease causal factors

2.2 Genetic risk factors: variant spectrum and genotype correlations

2.3 Modifier genes / protective genetic factors (current evidence limitations)

2.4 Environmental and lifestyle risk factors / protective factors

2.5 Gene–environment interactions

3. Phenotypes (clinical presentation, progression, and HPO suggestions)

3.1 Core neuromuscular phenotype

3.2 Respiratory phenotype

3.3 Cardiac phenotype

3.4 Quality‑of‑life impact

4. Genetic / molecular information

4.1 Causal gene

4.2 Functional consequences

4.3 Variant types and testing approaches (high level)

5. Environmental information

6. Mechanism / pathophysiology (with ontology suggestions)

6.1 Causal chain (current understanding)

6.2 Pathways and cellular processes highlighted in retrieved sources

6.3 Ontology suggestions

7. Anatomical structures affected

8. Temporal development (onset and progression)

9. Inheritance and population

9.1 Epidemiology (recent estimates)

9.2 Healthcare utilization and cost (real‑world)

9.3 Sex ratio

10. Diagnostics

10.1 Core diagnostic approach (from retrieved sources)

10.2 Respiratory monitoring as part of longitudinal assessment (2024 UK guideline)

10.3 Early diagnosis / screening

11. Outcomes / prognosis

11.1 Survival and causes of death (recent cohort data)

11.2 Disease milestones and supportive technology utilization (Italy)

12. Treatment

12.1 Standard of care / supportive care (respiratory)