Duchenne muscular dystrophy

Duchenne muscular dystrophy is a severe, progressive form of muscular dystrophy that mainly affects boys. Weakness usually begins around age four in the thighs and pelvis, then spreads to the arms, and most affected people can no longer walk by about age twelve. Muscles may look enlarged because fat replaces muscle, scoliosis is common, and some people have intellectual disability. It is caused by mutations or deletions in the large dystrophin gene on the X chromosome and follows an X-linked recessive pattern, with about two thirds of cases inherited from the mother and one third new mutations. Elevated creatine kinase and genetic testing support diagnosis. There is no cure, but physical therapy, glucocorticoids, assisted ventilation and newer exon-skipping and gene therapies help. Giovanni Semmola described the disease in 1834, and it is named for Guillaume Duchenne.