IDH1 and obesity due to melanocortin 4 receptor deficiency: Moreover, Koh et al. [27] reported for the first time that cytosolic NADP+-dependent isocitrate dehydrogenase (IDPc) plays a critical role in fat and cholesterol biosynthesis, showing that transgenic mice with overexpressed IDPc exhibited fatty liver, hyperlipidemia, and obesity without an increase in caloric intake or change in diet composition, converting IDPc into a potential therapeutic target for abnormal fat synthesis.