What causes 22q11.2 deletion syndrome?
About 90% of the time, this syndrome occurs randomly, meaning that neither parent has the chromosome deletion. The other 10% of the time, the deletion is inherited. If a parent is not diagnosed with 22q, the only way to know if they are a carrier is by genetic testing which is done through bloodwork. Parents without the deletion are not at an increased risk of having a second child affected even if they already have a child with this condition, but a parent who knows they have 22q always has a 50% chance of passing it on.