diff --git a/app/src/interfaces/input-rich-text-md/edits.ts b/app/src/interfaces/input-rich-text-md/edits.ts
index 4013311165..f35d7c80b8 100644
--- a/app/src/interfaces/input-rich-text-md/edits.ts
+++ b/app/src/interfaces/input-rich-text-md/edits.ts
@@ -26,8 +26,8 @@ type AlterationFunctions = Record<
 export type CustomSyntax = {
 	name: string;
 	icon: string;
-	prefix: string;
-	suffix: string;
+	prefix: string | null;
+	suffix: string | null;
 	box: 'inline' | 'block';
 };
 
@@ -228,6 +228,9 @@ const alterations: AlterationFunctions = {
 	custom(selection, { cursorTo, cursorHead }, options) {
 		if (!options) return { newSelection: selection, newCursor: cursorHead };
 
+		if (!options.prefix) options.prefix = '';
+		if (!options.suffix) options.suffix = '';
+
 		if (options.box === 'block') {
 			// Multiline
 			let newSelection = selection;