diff --git a/gatk.wdl b/gatk.wdl
index 87fa1046be22020b0a7b37b638d6c30084c43519..020adc7646d683da28cc97baa68a263b7a2b715e 100644
--- a/gatk.wdl
+++ b/gatk.wdl
@@ -259,6 +259,7 @@ task MuTect2 {
         String tumorSample
         String? normalSample
         File? panelOfNormals
+        File? panelOfNormalsIndex
         Array[File]+ intervals
 
         Int memory = 4