MALAT1 and major depressive disorder: In contrast to well documented mutations of HCN and KCNQ channel genes in a spectrum of epileptic diseases (Nappi et al., 2020; Rivolta et al., 2020), genetic studies in depressed patients have not conclusively acknowledged a convincing association between single nucleotide polymorphisms (SNPs) in HCN or KCNQ channel genes and depression.