The protein predicted to be defective in individuals with Fanconi anemia complementation group J ( FA- J), FANCJ, is a missing component in the Fanconi anemia pathway of genome maintenance. Here we identify pathogenic mutations in eight individuals with FA- J in the gene encoding the DEAH- box DNA helicase BRIP1, also called FANCJ. This finding is compelling evidence that the Fanconi anemia pathway functions through a direct physical interaction with DNA.