TFRC and obesity due to melanocortin 4 receptor deficiency: Of note, Tfrc fat‐conditional knockout mice showed impaired thermogenesis, increased insulin resistance, and low‐grade inflammation accompanied by iron deficiency and mitochondrial dysfunction,13 which highly support our clinical findings that missense variant p.I337V of TFRC may affect TFRC protein stability, as well as decreased thermogenic and mitochondrial gene levels, thus increase obesity risk.