A group of disorders including Paget disease of bone (PBD), inclusion body myopathy (IBM), and less frequently frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Phenotypic presentation and severity are highly variable, and individuals within the same family may present with different associated conditions. The disease is SQSTM1-related multisystem proteinopathy (Monarch Disease Ontology id MONDO_0800464).