Fixing situation when Molart started with variation overlay not having the aa change information

frontend-js/src/main/js/map/structure/MolArt.js

@@ -223,7 +223,11 @@ var retrieveVariants = function(customMap, elementId) {
       var geneVariants = aliasOverlayData[i].getGeneVariants();
       for (let i = 0; i < geneVariants.length; i++){
         var variant =  geneVariants[i];
-        overlayVariants = overlayVariants.concat(processGeneVariant(variant));
+        if (variant.getAminoAcidChange() !== null) {
+          // not all variants need to have an aminoacid change associated
+          overlayVariants = overlayVariants.concat(processGeneVariant(variant));
+        }
+        
       }
 
       if (overlayVariants.length > 0){