diff --git a/client/src/components/geneExpression/index.js b/client/src/components/geneExpression/index.js
index 7fe4600a..49d2fd36 100644
--- a/client/src/components/geneExpression/index.js
+++ b/client/src/components/geneExpression/index.js
@@ -177,7 +177,7 @@ class GeneExpression extends React.Component {
 
           const indexOfGene = upperWorldGenes.get(upperGene);
 
-          if (!indexOfGene) {
+          if (indexOfGene === undefined) {
             return keepAroundErrorToast(
               `${
                 genes[upperGenes.get(upperGene)]