In all words beginning <gn> the <g> is silent.
gnarled gnat gnash gnaw gnome gnu
In all words ending in <gn> or <gne> the <g> is silent.
align assign benign campaign champagne Cologne consign deign design feign foreign impugn malign reign resign sign sovereign
In the word lasagna (aka lasagne) the combination <gn> is pronounced nj.