This presumed domain has no known function. It is found in one or two copies in several Caenorhabditis elegans proteins. It is roughly 130 amino acids long. The domain contains 12 conserved cysteines which suggests that the domain is an extracellular domain and that these cysteines form six intradomain disulphide bridges. The GO annotation for this protein indicates that it has a function in nematode larval development and has a positive regulation of growth rate.