Table I.

Comparison of clinical manifestations and histopathology of dystrophin-null mice, dogs and humans

Feature	Humans	Mice	Dogs
Clinical manifestations
Birth body weight	Normal	Normal	Normal
Adult body weight	< Normal	≥ Normal	< Normal
Clinical course	Severe, progressive	Mild, non-progressive	Severe, progressive
Lifespan	25% of normal	75% of normal	25% of normal
Neonatal death	Rare	Rare	~25% of affected dogs
Age at first clinical signs	2–4 years old	≥ 15 months	Birth to 3 months
Loss of ambulation	Common at early teenage	Rare	Uncommon
Muscle wasting	Progressive	Minimal until ≥ 15 months	Progressive
ECG abnormalities	Frequent	Frequent	Frequent
Cardiomyopathy	Evident at 16 years	≥ 20 months; dilated (female) and hypertrophic (male)	Detectable at 6 months by echocardiography
Cognitive and CNS defects	1/3 of affected individuals	Mild	No information available
Histopathology
At birth	Minimal	Minimal	Minimal
Acute necrosis	None	2–6 weeks	None
Limb muscle fibrosis	Extensive and progressive	Minimal in adult	Extensive and progressive
Muscle regeneration	Poor	Robust	Poor

Adapted from (McGreevy et al., 2015). Shading indicates characteristics that are similar to human disease.