The dysfunction of the adipose tissue and the hormones that it produces, such as leptin, supposes a susceptibility to neurodegenerative diseases associated with obesity and metabolic disorders, since the neuroprotective effects that have been evidenced in the actions of leptin could be influenced by the resistance to leptin that is characteristic of disorders such as obesity, decreasing it’s neuroprotective effect and contributing to the pathogenesis of different neurodegenerative diseases, such as AD [38, 39]. The gene discussed is LEP; the disease is metabolic disease.