In these cases, transient knockdown by morpholino microinjection has been used for years to quickly assess the phenotypic consequence of a specific loss-of-function for CHD2 in epileptic encephalopathy (Galizia et al., 2015), CAPN1 in the context of Hereditary Spastic Paraplegia (Gan-Or et al., 2016), ABCC6 in Pseudoxanthoma elasticum (Van Gils et al., 2018), SBDS in Shwachman–Bodian–Diamond syndrome (Venkatasubramani and Mayer, 2008), or VARS in epilepsy (Siekierska et al., 2019). The gene discussed is CAPN1; the disease is hereditary spastic paraplegia.