Although they have not been found to be associated with DD-related traits by recent GWAS [6,7,8,9] and in a large cross-linguistic sample [10], nine genes have been replicated in at least one independent sample by candidate genes studies: DYX1C1, DCDC2, KIAA0319, C2orf3, MRPL19, ROBO1, FAM176A, NRSN1, KIAA0319L and FMR1 [11]. The gene discussed is ROBO1; the disease is dentin dysplasia.