More specifically, tanycytes are important in the regulation of body fat mass and leptin responsiveness.21, 22, 23, 39 Tanycytes could be the initial target cells for anti‐obesity effect exerted in the brain by leptin, a peptide released from fat tissue in relation to fat mass that may reach tanycytes via the blood, as suggested previously.23 IL‐6 produced in the brain may exert a similar anti‐obesity effect after reaching its receptor on tanycytes via the CSF. The gene discussed is IL6; the disease is obesity due to melanocortin 4 receptor deficiency.