Neurodevelopmental, emotional, and behavioural problems in Duchenne muscular dystrophy in relation to underlying dystrophin gene mutations

AIM: Duchenne muscular dystrophy (DMD) is associated with neuropsychiatric disorders. The aim of the study was to characterize the DMD neuropsychiatric profile fully and to explore underlying genotype/phenotype associations. METHOD: One hundred and thirty males with DMD (mean age 9y 10mo, range 5-17y) in four European centres were included and completed IQ assessment and a neurodevelopmental-screening questionnaire. Of these, 87 underwent comprehensive neuropsychiatric assessment using structured diagnostic interview and parent-reported questionnaires. RESULTS: The overall mean score on the neurodevelopmental questionnaire was significantly abnormal compared with the general population of children (p<0.001). On average, intelligence was below the population mean, with intellectual disability observed in 34 males (26%). Autistic spectrum disorder was identified in 18 (21%), hyperactivity in 21 (24%), and inattention in 38 (44%). Clinical levels of internalizing and externalizing problems were observed in 21 (24%) and 13 (15%) respectively. Over a third of males scored more than two measures of emotional, behavioural, or neurodevelopmental problems. Males with mutations at the 3' end of the DMD gene affecting all protein isoforms had higher rates of intellectual disability and clusters of symptoms. INTERPRETATION: Males with DMD are at very high risk of neuropsychiatric disturbance, and this risk appears to increase with mutations at the 3' end of the gene. Patterns of symptom clusters suggest a DMD neuropsychiatric syndrome, which may require prompt evaluation and early intervention.