diff --git a/VariantAnnotation/AnnotatedPositions/HgvsUtilities.cs b/VariantAnnotation/AnnotatedPositions/HgvsUtilities.cs
index af5cb7bf..0851b596 100644
--- a/VariantAnnotation/AnnotatedPositions/HgvsUtilities.cs
+++ b/VariantAnnotation/AnnotatedPositions/HgvsUtilities.cs
@@ -293,7 +293,7 @@ public static string FormatDnaNotation(string start, string end, string referenc
                     sb.Append(coordinates + "inv" + referenceBases);
                     break;
                 case GenomicChange.Duplication:
-                    sb.Append(coordinates + "dup" + referenceBases);
+                    sb.Append(coordinates + "dup");
                     break;
                 case GenomicChange.Substitution:
                     if (referenceBases == alternateBases)