SMC3

The SMC3 gene provides instructions for making a protein that is part of a family called the structural maintenance of chromosomes (SMC) family. Within the nucleus, these proteins help regulate the structure and organization of chromosomes.

Studies suggest that the SMC3 protein functions primarily within cells, where it helps control the activity of chromosomes during cell division. Before cells divide, they must copy all of their chromosomes. The copied DNA from each chromosome is arranged into two identical structures, called sister chromatids, which are attached together during the early stages of cell division. The SMC3 protein is part of a protein group (called the cohesion complex) that holds the sister chromatids together until the cell splits into two. Researchers believe that the SCM3 protein also plays important roles in stabilizing cells' genetic information and repairing damaged DNA.

Some of the protein produced from the SMC3 gene is exported from cells. The exported protein, which is usually called bamacan, may help connect cells together (cell adhesion) and likely plays a role in cell growth. Bamacan is a component of basement membranes, which are thin sheet-like structures that separate and support cells in many tissues. Although little else is known about the function of this protein outside the cell, it appears to be involved in normal development.

Cornelia de Lange syndrome - caused by mutations in the SMC3 gene

At least one mutation in the SMC3 mutation is known to cause a relatively mild form of Cornelia de Lange syndrome. This mutation, which is written as E488del, deletes a single protein building block (amino acid) from the SMC3 protein. This genetic change alters the structure of the protein, which disrupts its activity as part of the cohesion complex during cell division. Researchers are uncertain how changes in the SMC3 protein can result in the developmental problems characteristic of Cornelia de Lange syndrome.