💡 What does “severe phenotype” mean in Duchenne muscular dystrophy (DMD)? When doctors talk about a phenotype, they’re referring to the way a condition shows up in someone’s body, the physical traits and symptoms that result from their genetics. In Duchenne, a severe phenotype usually means the condition progresses more quickly, often with earlier loss of abilities like walking, climbing stairs, or raising arms. This can also bring earlier complications with breathing, heart health, and other a