pediatrics
Duchenne Muscular Dystrophy and Becker Muscular Dystrophy
Symptoms and Signs
This disorder affects approximately 20/100,000 live male births and manifests typically between 2 and 3 years of age ( Symptoms and signs references ). Weakness affects proximal muscles, typically in the lower limbs initially. Children frequently toe walk and have a waddling gait and lordosis. They have difficulty running, jumping, climbing stairs, and rising from the floor. Children fall frequently, often causing arm or leg fractures (in approximately 20% of patients) ( Consequences of cardiac muscle involvement include Dilated Cardiomyopathy , Compared to Duchenne dystrophy, Becker dystrophy affects < 8/100,000 live male births, typically becomes symptomatic much later, and is milder ( Symptoms and signs references ). Ambulation is usually preserved until at least age 15, and many children remain ambulatory into adulthood. Most affected children survive into their 30s and 40s. 1.Kariyawasam D, D'Silva A, Mowat D, et al: Incidence of Duchenne muscular dystrophy in the modern era; an Australian study.Eur J Hum Genet30(12):1398-1404, 2022. doi: 10.1038/s41431-022-01138-2 2.McDonald DG, Kinali M, Gallagher AC, et al: Fracture prevalence in Duchenne muscular dystrophy.Dev Med Child Neurol44(10):695-698, 2002. doi: 10.1017/s0012162201002778 3.Duan D, Goemans N, Takeda S, et al: Duchenne muscular dystrophy.Nat Rev Dis Primers7(1):13, 2021. doi: 10.1038/s41572-021-00248-3 