22-year girl, came with the complaint of not gaining weight. BMI 17, Normal CBC, TSH, Protein, Creatinine, SGPT, RBS normal serology. negative gamma interferon.

Mild elevated LDL, Chest x-ray normal. USG  ovarian cyst on left side 20*32 mm, fasting sugar 73 and fasting Insulin level 1.6 only. What can be the metabolic defect?