SQSTM1 and frontotemporal dementia: To validate whether cyclin F p.S621G causes p62 solubility defects in ALS and FTD patient derived cells, we repeated the soluble-insoluble protein analysis in human primary fibroblast cultures from non-disease control and a symptomatic ALS and FTD-affected CCNF p.S621G patient that were cultured in technical triplicates.