Both groups of children with heart disease had significantly higher plasma GDF15 levels than gender‐ and age‐matched healthy control children (Fig 6A), consistent with previous findings that plasma GDF15 was increased in adult heart disease (Wollert & Kempf, 2012; Baggen et al, 2017; Wollert et al, 2017). The gene discussed is GDF15; the disease is heart disorder.