Molecular characteristics

The syndrome is caused by an error, also called mutation, in the PSMD12 gene, which is very important for memory and learning. All the mutations found in the children were absent from both parents. They are therefore described as de novo. In such case, the risk is very low for future children to have the same PSMD12 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.