SERPINI1 and familial encephalopathy with neuroserpin inclusion bodies: Mutations in neuroserpin result in the autosomal dominant inclusion body dementia (Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB))4, and mutants of neuroserpin in FENIB patients show accelerated rates of polymerization compared with wild type protein both at the protein level5, 6 and in cell models7, 8.