Although little is known about the process or timing of caecal patch development in mice, caecal patch morphology has recently been examined in 8-week-old C57Bl/6 wild type mice and littermates expressing the autism-associated R451C missense mutation in the Nlgn3 gene encoding the Neuroligin-3 neuronal cell adhesion molecule (Sharna et al. 2020). The gene discussed is NLGN3; the disease is autism.