The most important candidate genes are MSX1, PAX9, AXIN2, EDA, EDAR, EDARADD and WNT10A. Dominant loss-of-function mutations in MSX1, PAX9 and AXIN2 had been implicated in familial forms of non-syndromic tooth agenesis [21,22,23]. The gene discussed is AXIN2; the disease is tooth agenesis.