You can read about it here.
Complicating the issue is that the preserved remains are only "presumed" to be those of Leonardo. The church where he was buried was destroyed during the Revolution and bones reburied in the present chapel in 1874.
I can see how the question of a disguised self-portrait would intrigue art historians, but part of the attraction of the Mona Lisa is the mystery that surrounds it. Does settling the matter merit such drastic measures, or should we let sleeping artists lie? What do you think?