Clinical expression of developmental coordination disorder in a large Canadian family.

Previous studies of the phenotype of developmental coordination disorder (DCD) have largely concentrated on population-based samples. The present study reports on an in-depth examination of a large Canadian family with eight children, after three children who were suspected to have DCD were referred for evaluation. Subsequently, five of the six children whose motor impairments could be measured, and the mother, met the diagnostic criteria for DCD as per the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders - fourth edition. The family members diagnosed with DCD showed remarkably similar profiles of motor difficulties. Additionally, the five children diagnosed with DCD had current speech articulation difficulties, with four of them having visited speech/language pathologists; the mother had a lateral lisp. More in-depth testing for three children revealed intact intellectual, academic and language comprehension skills. Three of the children diagnosed with DCD were obese. The present report highlights familial clustering of DCD and the presence of comorbid conditions in the affected children.