SLC6A4 and Salla disease: Although GABA is known to be a primarily involved in consequences of SD, but sleep research in recent times has also pointed toward significant alterations in 5-HT neurotransmission as well as neurochemical metabolism (under the control of molecules like 5-hydroxytryptamine transporter, 5-HTT and Glycogen synthase kinase 3-β) as a direct consequence of SD (Benedetti et al., 1999, 2012; Monti et al., 2011; Zant et al., 2011; Elmenhorst et al., 2012; Sharma et al., 2015).