diff --git a/src/js/components/Beacon/VariantsForm.tsx b/src/js/components/Beacon/VariantsForm.tsx
index 66c9f7d7..8309bb47 100644
--- a/src/js/components/Beacon/VariantsForm.tsx
+++ b/src/js/components/Beacon/VariantsForm.tsx
@@ -59,7 +59,7 @@ const VariantsForm = ({ beaconAssemblyIds }: VariantsFormProps) => {
       placeholder: `A, C, G, T ${td('or')} N`,
       initialValue: '',
     },
-    assemblyId: { name: 'Assembly ID', rules: [{}], placeholder: '', initialValue: '' },
+    assemblyId: { name: 'Assembly ID', placeholder: '', initialValue: '' },
   };
 
   const variantsError = beaconAssemblyIds.includes('error');
diff --git a/src/js/types/beacon.ts b/src/js/types/beacon.ts
index 833e6444..976ea11d 100644
--- a/src/js/types/beacon.ts
+++ b/src/js/types/beacon.ts
@@ -9,7 +9,7 @@ export type BeaconAssemblyIds = string[];
 
 export interface FormField {
   name: string;
-  rules: Rule[];
+  rules?: Rule[];
   placeholder: string;
   initialValue: string;
 }