LRP6 and tooth agenesis: Pathogenic alterations in MSX1 (Msh homeobox-1, OMIM *142983), PAX9 (Paired box gene-9, OMIM *167416), AXIN2 (Axis Inhibitor-2, OMIM *604025), EDA (Ectodysplasin-A, OMIM *300451), WNT10A (Wingless-Type MMTV Integration Site Family, Member 10a, OMIM *606268), LRP6 (Low Density Lipoprotein Receptor-Related Protein-6, OMIM *616724), KREMEN1 (Kringle Domain-Containing Transmembrane Protein-1, OMIM *609898) have been reported in the literature to cause non-syndromic hypodontia/oligodontia [2,3,4,5,6,7].