Most individuals with 22q11.2DS are missing a small part of chromosome 22 known as 22q11.2.
A human cell normally contains 46 chromosomes (23 from each parent). Chromosomes are thread-like structures found in every cell of the body, which carry hundreds of genes each. As a result of this deletion at chromosome 22q11.2, an estimated 40 to 60 genes are missing.
Other single-gene disorders and chromosome disorders can also cause features similar to those seen in 22q11.2DS.
If your child is found to have 22q11.2DS, both parents can be tested to check if it is hereditary. In 90% of cases, neither parent has the chromosome 22q11.2 deletion.
Everyone has two copies of each chromosome in their body’s cells, one copy from each parent. 22q11.2DS follows a dominant inheritance pattern. This means that having one chromosome 22 with the deletion can cause features of 22q11.2DS.
A parent with a chromosome 22q11.2 deletion has a 50% chance of passing it down to their offspring.
