Two functional copies of ROBO1 is required in brain development to acquire normal reading development and dyslexia may be caused by partial haplo-insufficiency for ROBO1.[17] Another candidate gene for dyslexia is DCDC2 which is located in the DYX2 locus and DCDC2 localizes to the regions of the brain where fluent reading occurs.[18] Though reports of candidate genes of dyslexia are accumulating none of the studies are replicated so far. This evidence concerns the gene ROBO1 and dyslexia.