diff --git a/itk/CMakeLists.txt b/itk/CMakeLists.txt
index e71d16ae..da2629ff 100644
--- a/itk/CMakeLists.txt
+++ b/itk/CMakeLists.txt
@@ -20,18 +20,18 @@
 # enough that it won't be a significant issue, since there appears to be
 # only so much we can do to sort it out...
 
-if (ENABLE_ITCL AND NOT DEFINED ENABLE_ITK AND NOT DEFINED DISABLE_TCL)
+if (ENABLE_ITCL AND NOT DEFINED ENABLE_ITK AND NOT DISABLE_TCL)
   set(ENABLE_ITK ON)
-endif (ENABLE_ITCL AND NOT DEFINED ENABLE_ITK AND NOT DEFINED DISABLE_TCL)
+endif (ENABLE_ITCL AND NOT DEFINED ENABLE_ITK AND NOT DISABLE_TCL)
 
-if (NOT ENABLE_ITK AND NOT DEFINED DISABLE_ITCL AND NOT DEFINED DISABLE_TCL)
+if (NOT ENABLE_ITK AND NOT DISABLE_ITCL AND NOT DISABLE_TCL)
   find_library(ITK_SYS_LIBRARY NAMES itk3)
 
   if (NOT ITK_SYS_LIBRARY AND NOT DEFINED ENABLE_ITK)
     set(ENABLE_ITK "ON" CACHE BOOL "Enable itk build")
   endif (NOT ITK_SYS_LIBRARY AND NOT DEFINED ENABLE_ITK)
 
-endif (NOT ENABLE_ITK AND NOT DEFINED DISABLE_ITCL AND NOT DEFINED DISABLE_TCL)
+endif (NOT ENABLE_ITK AND NOT DISABLE_ITCL AND NOT DISABLE_TCL)
 set(ENABLE_ITK "${ENABLE_ITK}" CACHE BOOL "Enable itk build")
 
 if (ENABLE_ITK)