What causes IDD?

Intellectual and Developmental Disabilities (IDD) have a variety of causes, and often are attributed to a combination of factors.

Most commonly, they are present at birth due to:

• Genetic conditions (including Down syndrome, Fragile X syndrome, and phenylketonuria)
• Complications during pregnancy (such as alcohol exposure or infection)
• Difficulties during labor or delivery (such as lack of oxygen)

In some cases, disabilities develop later in life due to illnesses such as meningitis or whooping cough, or from a traumatic brain injury.