Animal Models of Down Syndrome

Is intellectual disability a treatable feature of persons with Down syndrome? Researchers have made tremendous progress in the last 30 years, from creating the first mouse model of Down syndrome to completing the first major clinical trial for cognitive impairment in people with Down syndrome. Until recently, normalizing brain development and function seemed too lofty a goal, and indeed, even proposing a candidate therapy requires answering a number of difficult questions. How does trisomy 21, a molecular diagnosis, cause the clinical phenotypes of Down syndrome? When, where, and how do trisomic genes act to disrupt normal development and which genes are involved with which outcomes? Which brain regions and behaviors are most impaired? Is there an early developmental window of time during which treatments are most effective? This article discusses how animal models such as laboratory mice can be used to understand intellectual disability and to develop new treatments for cognitive impairment.