Catatonia in Down syndrome

Down syndrome, due to an extra chromosome 21, occurs in 250,000 children and adults in the United States, making it the country's most common chromosomal disorder. Inherited heart defects, thyroid cancer, celiac disease and developmental disabilities are common Down syndrome complications. Only recently has catatonia, a behavioral condition marked by new onset immobility, mutism, withdrawal and other behavioral abnormalities, been recognized in Down syndrome.