Duchenne MD

defining characteristics

Pseudohypertrophy (large calves), scoliosis, lumbar lordosis, protuberant abdomen, toe walking, Gower’s sign,  mental deficits

disease development

Caused by X-linked recessive mutation of dystrophin, resulting in absent (or <5%) dystrophin. W/o dystrophin, the sarcolemic membranes are leaky, there's secondary inflammation from necrosis, and cycles of degeneration & regeneration.

potential causes

Absent dystrophin


Most common MD, especially in children
1/3000 live births

risk factors


Histology? Increased CT, fibrofatty and macrophage infiltration, variable muscle fiber size and abnl cells, bluish fibers are regenerating (inc DNA)
CK levels 10-100x>nl

conventional treatment

Steroids at early age prolongs ability to walk


Associated w/ dilated cardiomyopathy
No cure! Limited life expectancy