In addition to the characteristic physical features and decreased mental abilities, other health problems frequently are seen in people with Down syndrome. These include:
Low levels of thyroid hormone
Skeletal problems such as joint instability
Poor weight gain in infants
Kidney and urinary tract anomalies
People with Down syndrome develop leukemia more often than those without the disorder, and they are more likely to develop infections, problems with the immune system, skin disorders and seizures.
Infants with Down syndrome usually develop more slowly than other children of the same age, although a wide variation is seen. Language development is typically much slower, as is motor development. Their body strength may seem a little weak. For example, most toddlers walk between 12 and 14 months of age, but toddlers with Down syndrome walk between 15 and 36 months.