novel maf mutation in a family with congenital cataractmicrocornea syndrome purpose to further unravel the molecular genetic background for the association congenital cataractmicrocornea ccmcmethods dna variation was pointed out by direct dna sequencing of 13 lensexpressed cataract genes from three ccmc families and one isolated case the mutation screening included seven crystalline genes two gap junction protein genes and four lens expressed regulatory genesresults a dna variation in the basic leucine zipper transcription factor vmaf musculoaponeurotic fibrosarcoma oncogene homolog gene maf was identified in one family the mutation c895ca changes arginine 299 to a serine residue and the substitution destroys the basic region of the dna binding domain of maf leucinezipper mutations were not identified in the remaining ccmc patientsconclusions one novel mutation affecting a known cataract gene was identified among four unrelated individuals with presumed autosomal dominant congenital cataractmicrocornea syndrome the maf mutation parg299ser is the third mutation identified in association with the ccmc phenotype and all three mutations are located in the basic region of the dna binding domain in the maf protein omim 177075 this suggests that the basic region is a hot spot domain for ccmc associated mutations the identification of a novel mutation associated with the distinct cataractmicrocornea phenotype adds a new brick to the puzzle of molecular modeling of the lensanterior segment structures