Notably, Smc5/6 contains a SUMO ligase, Mms21/Nse2, which is important for the described functions of the complex (Bermúdez-López et al., 2015, Branzei et al., 2006, Zhao and Blobel, 2005), and was recently identified to be mutated in a developmental disorder characterized by primordial dwarfism (Payne et al., 2014). The gene discussed is NSMCE2; the disease is isolated growth hormone deficiency type IA.