DNMT3A and overgrowth syndrome: Since its first description, the number of patients with documented DNMT3A overgrowth syndrome (DOS) has grown to more than 300 at present, whereas the repertoire of clinical manifestations has expanded to include obesity, cardiac defects, umbilical hernia, hypotonia, joint hypermobility, seizures, behavioral disorders, and other phenotypes (Hollink et al. 2017; Kosaki et al. 2017; Shen et al. 2017; Xin et al. 2017; Tatton-Brown et al. 2018; Jeffries et al. 2019; Balci et al. 2020; Ferris et al. 2021; Smith et al. 2021; Cecchi et al. 2022).