Mental retardation and lifetime events of Duchenne muscular dystrophy in Japan.

OBJECTIVE This study investigated the relationship between mental retardation and lifetime events in patients with Duchenne muscular dystrophy (DMD). METHODS The data on mental retardation and ages of lifetime events (first walking, loss of ambulation, introductions of ventilator support and tube nutrition and death) were collected retrospectively, and the relationships between the factors were analyzed. PATIENTS Among 194 DMD patients admitted to our hospital between 1995 and 2007, 74 patients underwent evaluation of their intelligence quotient (IQ). RESULTS Twenty-eight patients (38%) demonstrated mental retardation (IQ<70). DMD patients with mental retardation started walking later, required ventilator and tube nutrition support earlier, and died earlier than those without mental retardation. CONCLUSIONS Since the prognosis of DMD patients with mental retardation was worse than that of those without mental retardation, more careful treatment is necessary for DMD patients with mental retardation.