Some mechanisms have not been previously reported or, if so, have not been emphasized in the SLE literature, including osteoclast differentiation (135), synapse pruning (136, 137), mucin production in goblet and mucous cells (138), leptin signaling pathway (139), gastrin signaling (140), neurotrophin signaling (141, 142), and prolactin receptor signaling (143, 144), which may contribute to the female predominance in lupus. The gene discussed is MUC5AC; the disease is systemic lupus erythematosus.