Myotonic dystrophy

• AD inheritance
• childhood form presents in second decade w/distal weakness and myotonia (delay in relaxation after muscle contraction) (ie grip that won't relax)
• slowly progressive w/multisystem involvement (male pattern baldness, arrthymias, testicular atrophy,
• congenital form presents as hypotonic infant w/feeding difficulty and characteristic facies (fish mouth)

CHLA Board Review 2005