WNT3

The WNT3 gene is part of a large family of WNT genes, which play critical roles in development before birth. WNT genes provide instructions for making proteins that participate in chemical signaling pathways in the body. These pathways control the activity of certain genes and regulate the interactions between cells during embryonic development.

Research in animals indicates that the protein produced from the WNT3 gene is critical for the outgrowth of the limbs in the developing embryo. The WNT3 protein also appears to play an important role in determining the anterior-posterior axis (the imaginary line that runs from head to tail in animals) during the earliest stages of embryonic development. Additionally, the effects of mutations in the human WNT3 gene suggest that the protein may be involved in the normal formation of the facial features, head, heart, lungs, nervous system, skeleton, and genitalia.

tetra-amelia syndrome - caused by mutations in the WNT3 gene

A mutation in the WNT3 gene has been shown to cause tetra-amelia syndrome among members of one large family from Turkey. This mutation, which occurs in both copies of the WNT3 gene in each cell, replaces one protein building block (amino acid) with a premature stop signal in the instructions for making the WNT3 protein. This mutation is written as Gln83Ter or Q83X.

Researchers believe that the Gln83Ter mutation results in the production of an abnormally short, nonfunctional version of the WNT3 protein. Loss of the WNT3 protein disrupts normal limb formation before birth and leads to the other serious birth defects associated with tetra-amelia syndrome.