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). This evidence concerns the gene CAPN1 and pseudoxanthoma elasticum (inherited or acquired).