Ask the expert


        For parents, caregivers, health care providers, and teachers, concerns and questions often arise regarding the care and well-being of individuals with Cornelia de Lange Syndrome. 

Mosaicism, means there are different groups of cells with different genetic make-up in a person. This means that some cells in the person will have the mutation and others will not. Mosaicism has been found to occur frequently in CdLS. 

Approximately 15-20% of individuals with classic features of CdLS have mosaic changes in NIPBL; and although it is rare, individuals with CdLS can also have mosaic changes in SMC3, RAD21 or SMC1A. These mosaic changes cannot be found using genetic testing that examines an individual’s DNA from their white blood cells.



Mosaicism should be considered in individuals with CdLS in whom a variant in a gene known to cause CdLS cannot be detected in blood cells, in which case other tissues such as fibroblasts (skin), buccal (cheek) cells or bladder epithelial cells from urine should be studied.

our Questions and Answers of our experts


Legal Disclaimer

Please take note that the Ask the Expert service is comprised of volunteer professionals in various areas of focus. Answers are not considered a medical, behavioral, or educational consultation. Ask the Expert is not a substitute for the care and attention your child’s personal physician, psychologist, educational consultant, or social worker can deliver.


Do you have a question you would like to ask?

Ask a Question

Do You urgently need help? Contact the CdLS Foundation USA, Our Staff!