Involved in positive regulation of dendritic spine morphogenesis and positive regulation of synapse assembly. Predicted to be located in nucleoplasm. Predicted to be active in synaptonemal complex. Is expressed in brain; hindgut diverticulum; liver; placenta; and yolk sac. Orthologous to human FAM9B (family with sequence similarity 9 member B) and FAM9C (family with sequence similarity 9 member C). [provided by Alliance of Genome Resources, Apr 2022]