Detailed investigation of a person with ACC may find a known cause for the disorder. Where ACC is thought to have occurred as the result of an infection or exposure to a medication, drug or excess alcohol, the risks of it recurring is reduced if the same exposure does not occur in the next pregnancy.
Sometimes a known syndrome is suspected by the presence of other problems such as a cleft lip or differences in how fingers have developed. Syndromes including ACC as a feature can be inherited through families or occur for the first time in an affected person. For individuals in whom a genetic or chromosomal cause is suspected there are a growing number of tests to look for changes in their genes or chromosomes. These are not currently available for all conditions. Your paediatrician or geneticist will be able to advise you further on this.
For the majority of families we are currently unable to say for certain how ACC has happened in an individual and how likely it is to happen again. For Aicardi syndrome the change is thought to occur in a gene on the X chromosome. Studies of many families with Aicardi syndrome indicate that the recurrence risk is very low.