GCB Masthead
Down Syndrome Down Syndrome is the most common genetic cause of mental retardation, with a prevalence of 1:800-1:1,000 live births. It is caused by non-dysjunction of chromosome 21 prior to or during conception. The diagnosis of Down syndrome is made by chromosome analysis, which can be initiated prenatally due to identified risk factors such as maternal age (>35 years), or postnatally due to the characteristic appearance of the infant. In recent years, the number of Down syndrome pregnancies has increased, most likely due to a concurrent increase in maternal age. Nonetheless, the number of terminated pregnancies has also increased, leading to a slight reduction in the prevalence of Down syndrome births. The phenotype of Down syndrome includes a variety of physical and neurobehavioral abnormalities. In addition to cardiac, gastrointestinal, and skeletal malformations, sensory, endocrine, and dermatological problems constitute the main life-long concerns in Down syndrome. From the neurologic viewpoint, cognitive deficit that includes some selective impairments (e.g., language delay), seizures, and behavioral abnormalities (e.g., attentional difficulties, oppositional disorder, autistic features) are the main manifestations. In adults, major neurobehavioral abnormalities include Alzheimer's disease (75% in patients >60 years) and psychiatric disorders such as depression (~6%). The recent sequencing of chromosome 21 has raised expectations with regard to delineating the pathogenesis of the major manifestations in Down syndrome, as well as in terms of explaining the neurobehavioral variability of the disorder. At present, over 300 genes are predicted on chromosome 21. Several of these genes are part of sets involved in the same biological system; approximately 10 genes are likely to play a role in the pathogenesis of abnormal brain development and neurodegeneration.

Research Projects

A 12-week double blind placebo controlled clinical trial to evaluate the safety and efficacy of rivastigmine in children and adolescents (ages 10-18) with Down syndrome

Gene Expression and Genetic Mental Retardation

Neuropsychiatric Disorders in Down Syndrome

Genetic and Environmental Factors Related to Congenital Heart Disease in Down Syndrome