INS and obesity due to melanocortin 4 receptor deficiency: Moreover, in the KEGG pathway-enriched data, genes with higher enrichment were mainly related to insulin secretion and axon guidance, which coincides with the pathological mechanism of PCC/PGLs patients, wherein neuroendocrine tumors secrete a large amount of catecholamines to disrupt the endocrine and metabolism balance, leading to a series of clinical symptoms such as hypertension and obesity (Neary et al., 2011).