ARL6IP5 and obesity due to melanocortin 4 receptor deficiency: Similarly, the antioxidant enzyme Nrf2 gene expression demonstrated a significant increment in individuals with obesity in the Hp1-1, Hp2-1, and Hp2-2 groups after RIF compared with before RIF; the values were more than five-fold in Hp1-1 and Hp2-1 and more than eight-fold in Hp2-2.