Predicted to enable complement component C1q complex binding activity. Predicted to be involved in complement activation and positive regulation of apoptotic cell clearance. Located in extracellular space. Human ortholog(s) of this gene implicated in autistic disorder; autoimmune disease (multiple); complement deficiency (multiple); and renal cell carcinoma. Orthologous to several human genes including C4B (complement C4B (Chido blood group)). [provided by Alliance of Genome Resources, Apr 2022]