TFAP2B and Char syndrome: It is challenging to determine the genotype-phenotype relationship in BOFS and Char Syndrome patients due to the small sample size and the large spectrum of mutations affecting TFAP2A and TFAP2B. With recent advances in site-targeted mutagenesis in the C. elegans genome, it is an exciting possibility to generate worm strains carrying mutations of conserved residues in BOFS and Char Syndrome.