Molecular characteristics

The syndrome is caused by a change, also called mutation, in the CAMK2B gene, which is the genetic information to build the CAMK2B protein. The CAMK2B protein is highly expressed in the brain, and is very important for memory and learning, since it can regulate the strength of connections between nerve cells. When a person starts to learn something (e.g. learning a language), different nerve cells start to communicate to each other, and like this strengthen their connection. This increase in connectivity is the basis for learning and memory. It has been shown by many different research labs that changes in the function of the CAMK2B protein leads to disruptions in the possibility for nerve cells to connect and cause impairments in learning and memory.

All the mutations found in the children were absent from both parents. They are therefore considered as de novo. In such case, the risk is very low for future children to have the same CAMK2B mutation and be affected by the same disorder as the older brother or sister. This risk is however increased compared to that of the general population.

Although such occurrences have not been reported to date, each child of an affected individual has a 50% chance of being affected dependent on whether or not he or she inherits the mutated or normal copy of the gene from the affected parent.

Prenatal genetic counselling can be offered in families where the diagnosis has been molecularly confirmed.