Reduced or absent lower limb deep tendon reflexes, skeletal anomalies (bilateral talipes equinovarus, scoliosis, kyphoscoliosis, lumbar hyperlordisis), late ambulation, waddling
[orpha.net]
Prognosis for remaining ambulant is inversely related to age at onset with no case manifesting in infancy still walking at 10 years; and, conversely, no late-onset individual
[academic.oup.com]