Several mutated genes including Cyp26a1, Hoxd13 [25], Wnt-3a [26], Acd, Ptf1a, and Pcsk5 underlie a CRS-like phenotype in mice [10, 27], yet mutations in the human orthologs have never been identified in CRS patients. This evidence concerns the gene CYP26A1 and congenital rubella syndrome.