The H3K9 specific demethylase JmjC domain-containing histone demethylase 2A (JHDM2A) was well known to an important regulator of fatty acid metabolism, therefore loss of function of JHDM2A resulted in obesity and hyperlipidemia [21,22]. The gene discussed is KDM3A; the disease is obesity due to melanocortin 4 receptor deficiency.