diff --git a/public/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/tools/RegionAfCount.scala b/public/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/tools/RegionAfCount.scala
index f7c4324d29d3da45676f872a270738d9f275789e..51cfd8e3882d2b501afcc7584c3d56bd7c1d6bc0 100644
--- a/public/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/tools/RegionAfCount.scala
+++ b/public/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/tools/RegionAfCount.scala
@@ -47,7 +47,7 @@ object RegionAfCount extends ToolCommand {
       c.copy(outputFile = x)
     }
     opt[File]('V', "vcfFile") unbounded () minOccurs 1 action { (x, c) =>
-      c.copy(vcfFiles = x :: c.vcfFiles)
+      c.copy(vcfFiles = c.vcfFiles ::: x :: Nil )
     }
   }