Additionally, the use of recombinant human IGF-1 (rhIGF-1) was associated with improvements in acanthosis nigricans, and levels of plasma glucose, insulin, fructosamine and HbA1c in patients with extreme insulin resistance syndromes, including congenital generalized lipodystrophy (CGL) [70]. This evidence concerns the gene INS and congenital generalized lipodystrophy.