Coffin-Siris syndrome is a condition that affects several body systems. Although there are many variable signs and symptoms, hallmarks of this condition include developmental disability, abnormalities of the fifth (pinky) fingers or toes, and characteristic facial features.

Coffin-Siris syndrome is caused by variants (also known as mutations) in one of several genes. Variants in the ARID1B gene are the most common known cause of the condition. Variants in the ARID1A, SMARCA4, SMARCB1, SMARCE1, or SOX11 gene can also cause the condition. In addition, variants in a few other genes (listed below) have been found to each cause  a very small number of cases. In some of these cases, it is unclear if the condition should be considered Coffin-Siris syndrome or a similar but separate disorder. In many cases of Coffin-Siris syndrome, the genetic cause is unknown.

Coffin-Siris syndrome is a rare condition that, for unknown reasons, is diagnosed in females more frequently than in males. Approximately 200 cases have been reported in the medical literature.

Coffin-Siris syndrome appears to follow an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the disorder. However, the condition is not usually inherited from an affected parent, but occurs from new (de novo) variants in the gene that likely occur during early embryonic development.

Published Date: August 30, 2021
Published By: National Institutes of Health