Résumé : The branchio-oculo-facial syndrome (BOFS) is a rare disorder with approximately 50 sporadic and familial cases in the literature. We report on the clinical and molecular analyses of five additional patients with BOFS (two familial and three sporadic). DNA analysis of the TFAP2A gene associated with BOFS using DNA sequencing detected a mutation [c.763A>G (p.Arg255Gly)] in two unrelated patients. This mutation had been reported in another patient and indicates a probable mutational hotspot in the TFAP2A gene. We also detected three new mutations which are restricted to exons 4-6. These gene regions are almost free of any single nucleotide polymorphisms. An evolutionary sequence comparison showed a high degree of sequence conservation from humans to the honey bee (Apis mellifera) in exon 6 showing that this part of the protein is probably essential. Our study represents the second group of BOFS patients with molecular confirmation, expanding the phenotype and spectrum of mutations and limiting it to a restricted part of the gene. © 2010 Wiley-Liss, Inc.