diff --git a/quad/quadwriter/font.rkt b/quad/quadwriter/font.rkt
index 99a8ce26..07f02fd0 100644
--- a/quad/quadwriter/font.rkt
+++ b/quad/quadwriter/font.rkt
@@ -89,7 +89,7 @@
 
 (define (font-path-string? x)
   (and (path-string? x)
-       (member (path-get-extension (string->path x)) '(#".otf" #".ttf" #".woff"))
+       (member (path-get-extension (string->path x)) font-file-extensions)
        #true))
 
 (module+ test