SALL4

The SALL4 gene is part of a group of genes called the SALL family. These genes provide instructions for making proteins that are involved in the formation of tissues and organs during embryonic development. SALL proteins are transcription factors, which means they attach (bind) to specific regions of DNA and help control the activity of particular genes.

The exact function of the SALL4 protein remains unclear. Based on the function of similar proteins in other organisms (such as zebrafish and mice), it appears to play a critical role in the developing limbs. This protein may also be important for the development of nerves that control eye movement and the walls (septa) that divide the heart into separate chambers.

Duane-radial ray syndrome - caused by mutations in the SALL4 gene

More than 20 mutations in the SALL4 gene have been identified in people with Duane-radial ray syndrome (also called Okihiro syndrome) or conditions with very similar signs and symptoms (such as acro-renal-ocular syndrome). These mutations create a premature stop signal in the instructions for making the SALL4 protein. As a result, one copy of the SALL4 gene in each cell does not produce any protein. Researchers are investigating how a reduction in the amount of SALL4 protein disrupts eye, heart, and limb development and leads to the characteristic features of Duane-radial ray syndrome.