Determining neurodevelopmental manifestations in Duchenne muscular dystrophy using a battery of brief tests

We report neurodevelopmental manifestations in boys with Duchenne muscular dystrophy (DMD) and evaluate the correlations between mutation location and three neurodevelopmental abnormalities: intellectual disability, autism spectrum disorder, and attentional problems.This cross-sectional study included 55 Japanese boys with genetically confirmed DMD who visited the outpatient department of the National Center for Psychiatry and Neurology of Japan from October 2017 to April 2018. Neurodevelopmental manifestations were evaluated using the Raven's Colored Progressive Matrices (RCPM), the Parent-Interview Autism Spectrum Disorder Rating Scale-Text Revision (PARS-TR), and the Attention-Deficit Hyperactivity Disorder-Rating Scale.Among the 55 boys (mean [standard deviation, SD] age, 9.5 [1.6] years), 24 (43.6%) scored below -2.0 SD in RCPM, indicating intellectual disability. Further, 83% had DMD variants in exon 45 or downstream to it (P = 0.005). On the PARS-TR, 30 (55%) and 21 boys (38%) scored higher than the clinical cutoff score in childhood and present scores, respectively. Stereotyped behavior and restricted interests scores were found to decrease with age (P = 0.003 and P = 0.01, respectively).The results show that boys with DMD who have intellectual disability commonly have DMD variants in exon 45 or downstream to it. Stereotyped behavior and restricted interests improved with age, while intellectual disability did not.Understanding these characteristics of neurodevelopmental disability may reduce risky behaviors and improve the overall quality of life of patients with DMD.