Special symbols size issue with Firefox-4.0.1

[Yuri]

On http://en.wikipedia.org/wiki/Voiced_alveolo-palatal_fricative symbol 
on the right side is displayed in firefox with a very tiny size font. In 
Ubuntu and in Windows firefox displays the same symbol nicely with the 
large size font.

My fonts in xorg.conf are:
Section "Files"
         ModulePath   "/usr/local/lib/xorg/modules"
         FontPath     "/usr/local/lib/X11/fonts/misc/"
         FontPath     "/usr/local/lib/X11/fonts/webfonts"
         FontPath     "/usr/local/lib/X11/fonts/TTF/"
         FontPath     "/usr/local/lib/X11/fonts/OTF"
         FontPath     "/usr/local/lib/X11/fonts/Type1/"
         FontPath     "/usr/local/lib/X11/fonts/100dpi/"
         FontPath     "/usr/local/lib/X11/fonts/75dpi/"
         # from here -- my additions
         FontPath   "/usr/local/lib/X11/fonts/TrueType/"
         FontPath     "/usr/local/lib/X11/fonts/tmu/"
         FontPath   "/usr/local/lib/X11/fonts/cyrillic/"
         FontPath  "/usr/local/lib/X11/fonts/dejavu"
EndSection

What is wrong with the fonts that this special symbol isn't displayed 
with the proper size?

Yuri