A further gene array study in the midbrain region of HTX rats with congenital hydrocephalus suggested that abnormal expression of cholecystokinin (Cck), nuclear factor 1/X (Nfix), three galactose-binding soluble lectins (Lgals3), glutathione s-transferase a type (Gsta1), Xdh (xanthine dehydrogenase), a tissue factor pathway inhibitor (Tfpi-2) and the fork-head transcription factor BF-1 (Fkhr) may be associated with hydrocephalus (Miller et al., 2006). Here, CCK is linked to congenital hydrocephalus.