HACD2 and obesity due to melanocortin 4 receptor deficiency: Previous studies have shown that HACD2, an obesity‐related gene, plays an important role in the regulation of fatty acid synthesis.[12] Surprisingly, in our study, the replenishment of long‐chain fatty acids did not rescue the inhibition of PC cells proliferation caused by HACD2 deletion (Figure 2), suggesting that the regulatory effect of HACD2 on the proliferation of PC cells is dependent on its nonenzymatic function.