» Why does my child have Cornelia de Lange Syndrome and could I have another child with Cornelia de Lange Syndrome?

The genetic causes of CdLS are complex and research to fully understand all the genetic causes is still ongoing. The genetic make-up of a child cannot be changed after conception.

The CdLS spectrum has been associated with a change (mutation) in genetic material. Usually, CdLS is caused by a change in one of seven genes. Genes are individual genetic instructions in DNA that make us who we are. The seven genes associated with CdLS are: NIPBL, SMC1A, SMC3, RAD21, BRD4, HDAC8 and ANKRD11. A change in one of these genes affects what is known as the cohesin protein complex.

The cohesin complex has many functions. One of these includes regulating the process of a fertilised egg dividing many times during the development of a baby. This process requires all of the DNA (genetic material present) to produce a second copy of itself before it divides. Changes to the genetic code can occur when the DNA is copied. The cohesin complex also regulates the expression, structure and organisation of a person’s genetic code.

If a change in genetic code affects one of the seven genes associated with the CdLS spectrum, the cohesin complex does not function properly. This can cause altered human development and is believed to be the underlying cause of CdLS and syndromes in the CdLS spectrum.

The chances of having another child with the syndrome are very small. There are only a few known cases in the world of a couple having two children with the syndrome. We are therefore more than 97% sure it will not happen again in your family. Even though couples know that it is extremely unlikely that they will have another child with the syndrome they feel very unlucky, especially if it is their first child, and often believe that things will go wrong again if they have another child.