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Cornelia de Lange syndrome (CdLS) is genetic condition that affects how somebody grows and develops.


What is it like for siblings who have a brother or sister with Cornelia de Lange syndrome?

Lots of siblings have really good relationships with their brothers and sisters who have CdLS. Other siblings can find it difficult because their brothers or sister need lots of extra care and attention which can make them feel left out. They can feel embarrassed if people stare at their brothers and sisters when they are out and about. This is because people with CdLS may look and behave differently to other children. This can also make it hard to have friends round and do things that other families do.

What causes CdLS?

CdLS is very rare which means that very few people have it. People are born with CdLS; you cannot catch it like a cold. No one knows why some people have CdLS and it is no one’s fault.

What does it mean?

 Cornelia de Lange Syndrome can mean that someone

  • Is a bit smaller than average,
  • may have a Learning Difficulty
  • may have hands and arms which look different
  • may have seizures
  • may have Autism Spectrum Disorder
  • may have high eyebrows
  • may have widely spaced eyes and teeth
  • may have difficulties hearing things
  • may have more hair on their body
  • may have difficulties seeing
  • may have difficulties with their teeth
  • may have reflux which makes them sick a lot

What treatment is there?

Most people who have CdLS may need to take medicine every day. They might need to take more than one type of medicine. This may help to prevent sickness or seizures. Sometimes it can stop the seizures altogether.


Other people who have CdLS might need to wear hearing aids or might have Speech and Language Therapy or Occupational therapy to help with their development.

This has been read and approved for publication by CdLS Foundation UK and Ireland in July 2022 and will be reviewed and updated every 2 years