» What causes Cornelia de Lange Syndrome


The NIPBL gene codes for a protein which is part of the regulatory centre of cohesin and, along with another gene (MAU2) helps the ring to be loaded onto the duplicated DNA. Changes (mutations) in NIPBL can be found in approximately 70% of individuals with CdLS. Classic CdLS is usually caused by changes in NIPBL (13,14). The missense mutations (single small mutations) cause milder phenotypes than the loss of function mutations, as described on page 8. Deletions may occur in NIPBL in about 3% of those with CdLS. Also, there are quite a few people with classic CdLS who have been found to have mosaicism for mutations in NIPBL, which means that not all of the cells tested show the mutation (e.g. the mutation is unable to be found in a blood sample, but can be detected on a cheek swab which takes cells from the inside of the cheek (see below).

While individuals with the classic CdLS phenotype are likely to have changes in NIPBL, individuals with changes in the other causative CdLS genes can also fulfil the criteria for classic CdLS.

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