This cell system will be of great value in future efforts aimed to develop small molecule therapies for FENIB, aimed to increase NS degradation or to block polymer formation, as shown for a similar protein aggregation disease, alpha‐1 antitrypsin deficiency, for which a small molecule able to prevent alpha‐1 antitrypsin polymer formation has already been described (Lomas et al. 2021). Here, SERPINA1 is linked to familial encephalopathy with neuroserpin inclusion bodies.