diff --git a/src/Structure/ClassStructureTrait.php b/src/Structure/ClassStructureTrait.php
index f9a4ca3..3d4a237 100644
--- a/src/Structure/ClassStructureTrait.php
+++ b/src/Structure/ClassStructureTrait.php
@@ -104,6 +104,11 @@ public function jsonSerialize()
         $processed = array();
         if (null !== $properties) {
             foreach ($properties->getDataKeyMap() as $propertyName => $dataName) {
+                if (!isset($this->$propertyName)) {
+                    // Skip uninitialized properties
+                    continue;
+                }
+                
                 $value = $this->$propertyName;
 
                 // Value is exported if exists.