In the Drosophila FXS model, Dlp is constitutively elevated at the NMJ synapse, and reduction of Dlp (or dependent MMP1) in otherwise dfmr1 null mutants suppresses FXS synaptogenic phenotypes (Siller and Broadie, 2011; Friedman et al., 2013). The gene discussed is MMP1; the disease is fragile X syndrome.