A neuronal intermediate filament called peripheralin has been linked to inclusion bodies in motor neurons from people who have amyotrophic lateral sclerosis (ALS). A nucleotide insertion in intron 8 ( PRPHIVS8 -36insA ) and a 1 bp deletion in exon 1 have been identified as two additional peripherin gene PRPH variants in ALS cases. The assembly of the neurofilament network is disrupted as a consequence of the expression of this frameshift peripherin mutant in SW13 cells . ALS is frequently associated with reactive astrocytes, and human induced pluripotent stem cell (hiPSC)-derived astrocytes that contain ALS pathogenic mutations in VCP, SOD1, and C9orf72 frequently exhibit reduced intron retention (IR) .