Of the many genetic obesity syndromes, none have been as intensively studied as ob/ob
and db/db mice. These two mutant mice were originally identified over 30 years ago (1, 2)
and shown to be a result of two distinct single gene mutations residing on mouse
chromosomes 6 (ob) and 4 (db). The phenotypes and pathophysiologies of these two mice
have been studied for decades and described in well over 1000 publications. However, the
nature of the lesions or primary defects was not revealed until very recently. Perhaps the …