diff --git a/index.d.ts b/index.d.ts
index 51d283e..831701d 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -83,8 +83,7 @@ export interface FileWithHandle extends File {
 // and is implemented as part of microsoft/TSJS-lib-generator.
 
 export interface FileSystemHandlePermissionDescriptor {
-  fileSystemHandle: FileSystemHandle;
-  mode: 'read' | 'readWrite';
+  mode?: 'read' | 'readwrite';
 }
 
 export interface FileSystemHandle {