Usually. sign and symptoms of Duchennes muscular dystrophy are not noticed until ages 3 to 5 years. Typically weakness starts with the pelvic girdle. evidenced as difficulty running in the preschooler. Duchennes muscular dystrophy usually is not diagnosed in the infant or toddler period.Option A: Sucking is not the first sign of Duchennes muscular dystrophy.Option B: Sign and symptoms of muscular dystrophy are not noticed until ages 3 to 5 years.