SMC1A

The SMC1A gene provides instructions for making a protein that is part of a family called the structural maintenance of chromosomes (SMC) family. Within the nucleus, SMC proteins help regulate the structure and organization of chromosomes.

The protein produced from the SMC1A gene (which is usually called the SMC1 protein) 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 to one another during the early stages of cell division. The SMC1 protein is part of a protein group called the cohesion complex that holds the sister chromatids together.

Researchers believe that the SMC1 protein also plays important roles in stabilizing cells' genetic information, repairing damaged DNA, and controlling the activity of certain genes that are essential for normal development.

Cornelia de Lange syndrome - caused by mutations in the SMC1A gene

More than 20 mutations in the SMC1A gene have been identified in people with Cornelia de Lange syndrome. These mutations account for about 5 percent of all cases of this condition.

Most of the SMC1A gene mutations responsible for Cornelia de Lange syndrome change single protein building blocks (amino acids) used to make the SMC1 protein. These genetic changes alter the structure and function of the protein, disrupting its ability to regulate genes involved in development. These changes in gene regulation are likely responsible for the developmental problems characteristic of Cornelia de Lange syndrome.

Studies suggest that mutations in the SMC1A gene usually cause a form of Cornelia de Lange syndrome with relatively mild features. Compared to mutations in the NIPBL gene, which are a more common cause of the disorder, SMC1A gene mutations tend to cause less significant delays in development and growth and are less likely to cause major birth defects.