Disorders and Intellectual Disability
Figure 6-19 Model for impact of genetic or genomic changes on an individual’s cognitive, neurobehavioral, and motor development. Here, the observed profile of abilities in probands (solid boxes) shows the deleterious effect of a copy number variant (CNV) on the predicted profile expected from familial background (gray boxes). The phenotypic effect of a particular CNV varies among the three elements of neurodevelopment. The purple dotted line represents the diagnostic threshold (2 SD below the mean). A, In this family, the deleterious effect of the CNV on quantitative cognitive traits (e.g., IQ) results in a diagnosis of intellectual disability, whereas neurobehavioral and motor features do not fall within the clinically impaired range. B, In contrast, in a different family, because of different familial norms, the deleterious effect of the same CNV leads to a diagnosis of a neurobehavioral disorder (e.g., schizophrenia), but without intellectual disability or motor impairment. See Sources & Acknowledgments.