Proposed childhood disintegrative causes include:
- genetic factors
- environmental exposure to toxins or other substances
- autoimmune issues
- presence of other serious conditions
While childhood disintegrative disorder (CDD) and autism share many characteristics and are often closely linked, the two conditions are different and have distinctive characteristics. There are a number of cases, however, where children from the same family have been diagnosed with autism and childhood disintegrative disorder. According to Geraldine Dawson in an article published in the Journal of Autism and Developmental Disorders in 2000, "this would be evidence of a genetic etiology for autistic regression and further suggest that CDD and autism share a common genetic mechanism." The specific gene or group of genes has not been identified, and much further research is needed.
Childhood disintegrative disorder has been linked to toxins present in the environment. These include pesticides, herbicides, heavy metals (e.g. mercury), chemicals and certain plastics. Children exposed to high levels of toxins, or whose mothers were exposed during pregnancy, could be more susceptible to CDD. It is generally believed that while these toxins alone cannot cause childhood disintegrative disorder, or other forms of autism, they may act as a trigger for those genetically predisposed to the disorders.
The body's immune system is designed to fight foreign organisms to prevent illness and infection. One of the more complex possible childhood disintegrative disorder causes is an autoimmune disorder. In these cases, the body sees its own cells as foreign and begins to attack them. Researchers are not sure whether children with childhood disintegrative disorder are more susceptible to autoimmune disorders, or if their bodies respond differently to infection. Dr. Hossein, the author of The Medical Basis of Psychiatry, suggests that "a genetic predisposition to poor immunological functioning" may exist. Whatever the cause of the autoimmune issue, it causes the child's body to attack itself creating significant nerve cell damage.
Presence of other Disorders
Often, the presence of one or more medical conditions can trigger or exacerbate another. In the case of childhood disintegrative disorder, there are a number of conditions that appear to occur alongside it, or before it.
A type of metabolic condition called lipid storage disease causes fats to accumulate in the central nervous system. These fats can reach a toxic level and damage neural pathways. This may explain the loss of skills associated with childhood disintegrative disorder.
A serious brain infection known as subacute sclerosing panencephalitis causes damaging inflammation of brain tissues and kills nerve cells in the central nervous system. It is caused by a particular type of measles.
In tuberous sclerosis, benign tumors can develop in the brain, causing swelling and brain cell damage.
It is not currently clear whether these associated conditions can cause childhood disintegrative disorder, or whether they are also a result of similar genetic or environmental triggers.
Dawson, Geraldine. "What is Childhood Disintegrative Disorder, how is it different from autism, and what is believed to be its cause?" The Journal of Autism and Developmental Disorders. 2000.
Hossein, S. The Medical Basis of Psychiatry. Humana Press, 2008.