Trial of Leptin Replacement Therapy in Patients With Lipodystrophy

Inclusion Criteria: * age \> 6 years * Partial and generalized lipodystrophy * Serum leptin levels less than the 7th percentile of normal values reported by the 3rd National Health and Nutrition Examination survey (less than 7.0 ng/mL in females and less than 3/0 ng/mL in males) * Presence of at least one of the following metabolic abnormalities: 1. Type 2 Diabetes Mellitus 2. Fasting serum insulin \>20 uU/mL 3. Fasting serum triglycerides \> 300 mg/dL 4. Previous participation in leptin trial (Amgen 991265, GCRC 660) - for Part B of the Study. Exclusion Criteria: * Known liver disease due to causes other than non-alcoholic steatohepatitis. * Hematocrit of less than 30%. * Current alcohol or substance abuse. * Use of anorexigenic drugs, anabolic steroids, GH and thiazolidinediones * Active tuberculosis * Psychiatric disorder impeding competence or compliance * Malignancies * HIV infection * Subjects who have a known hypersensitivity to E. Coli derived proteins * Other condition, which in the opinion of the clinical investigators would impede completion of the study.