I once read that Mussolini was reluctant to implement anti-Jewish legislation despite German pressure but agreed to do so in exchange for the expulsion of Germans from Northern Italy (including South Tyrol).
The claim is that Northern Italy had a dense German population and, given the territorial demands of Germany to adjacent states such as Poland and Czechoslovakia to cede the areas populated with Germans, Mussolini had good reason to be afraid of the possibility of similar demands to Italy.
After the deal was done, the Germans were forcibly expelled to Germany while a minority had to sign declarations that they were in fact Italians.
Germany did not resist the expulsion because, for Hitler, anti-Jewish measures were more important than protecting Germans.
I wonder how much truth there is in this story.
A relevant Wikipedia article http://en.wikipedia.org/wiki/South_Tyrol_Option_Agreement