Table 1.

Characteristics of DMD

Level of Pathology	Definitions and Descriptors at Various Levels of the Disease
Genetic	X-linked, hereditary or spontaneous
Cellular	Absence of the protein dystrophin, mechanical weakening of the sarcolemma, inappropriate calcium influx, recurrent muscle ischemia, aberrant cell signaling, increased oxidative stress, histologic z-disk disruption, central nucleation, fiber size heterogeneity, reduced expression and mislocalization of dystrophin-associated proteins
Tissue	Intramuscular accumulation of fibrous connective and fatty tissue, pseudohypertrophy
Organ systems	Musculoskeletal system, nervous system, digestive system, immune system, cardiorespiratory system
Clinical	Lethal, progressive, 1:3500 live male births, muscle wasting and weakness, susceptibility to fatigue, muscle pain, elevated serum creatine kinase, myoglobinuria, Gower sign, lordosis, progressive difficulty with ambulation, contractures, contraction-induced injury, secondary disuse atrophy, increased fat mass, side effects of medications, cardiorespiratory failure