This domain has no known function. It is found in several C. elegans proteins. The domain contains 8-10 conserved cysteines that probably form 4-5 disulphide bridges. By inspection of the conservation of cysteines it looks like cysteines 1,2,3,4,9 and 10 are always present and that sometimes the pair 5 and 8 or the pair 6 and 7 are missing. This suggests that cysteines 5/8 and 6/7 make disulphide bridges.