diff --git a/Doc/source/designspaceLib/readme.rst b/Doc/source/designspaceLib/readme.rst
index cd772af32..68a700910 100644
--- a/Doc/source/designspaceLib/readme.rst
+++ b/Doc/source/designspaceLib/readme.rst
@@ -216,8 +216,6 @@ Attributes
 -  ``glyphs``: dict for special master definitions for glyphs. If glyphs
    need special masters (to record the results of executed rules for
    example). MutatorMath.
--  ``mutedGlyphNames``: list of glyphnames that should be suppressed in
-   the generation of this instance.
 -  ``kerning``: bool. Indicates if this instance needs its kerning
    calculated. MutatorMath.
 -  ``info``: bool. Indicated if this instance needs the interpolating
diff --git a/Lib/fontTools/designspaceLib/__init__.py b/Lib/fontTools/designspaceLib/__init__.py
index 3209feb3f..b8b962fc2 100644
--- a/Lib/fontTools/designspaceLib/__init__.py
+++ b/Lib/fontTools/designspaceLib/__init__.py
@@ -235,7 +235,6 @@ class InstanceDescriptor(SimpleDescriptor):
         self.localisedStyleMapStyleName = {}
         self.localisedStyleMapFamilyName = {}
         self.glyphs = {}
-        self.mutedGlyphNames = []
         self.kerning = True
         self.info = True