Disorders of any type of pathology may affect the nervous system at any point during its development. When pathology affects the nervous system early in development, the syndrome that results may not appear until months or years later, at a time when the child would normally start using the functions of the affected areas. Neurodevelopmental delay refers to significantly late performance of milestones in one or more functional domains, which is usually caused by a disorder. Sometimes a normal child will take longer for some part of their neurodevelopment, and then later catch up to their peers, so that delay is not always caused by a disorder.
Some common examples of neurodevelopmental disorders include neural tube defects, cerebral palsy, and intellectual disability. Neural tube defects involve syndromes that may occur with abnormal closure of the neural tube, which usually causes abnormal development of the spinal cord, or sometimes the brain. Cerebral palsy refers to syndromes that involve abnormal motor function from brain injury early in development. Intellectual disability refers to abnormalities of cognitive functions from abnormal development of the brain, particularly the cerebral cortex. This may occur from many causes, such as the genetic disorder Down syndrome. These neurodevelopmental disorders, and many others, may occur in isolation or a patient may have overlapping syndromes with features of several disorders.