Pathological proteins are abnormal proteins that can disrupt normal cellular functions and contribute to diseases. These proteins often misfold or aggregate, leading to toxic effects on cells. Common examples include amyloid beta in Alzheimer's disease and prion proteins in Creutzfeldt-Jakob disease. The presence of pathological proteins can trigger inflammatory responses and damage tissues, resulting in various health issues. Understanding these proteins is crucial for developing targeted therapies and diagnostic tools for diseases associated with protein misfolding and aggregation. Research continues to explore their roles in conditions like Parkinson's disease and Huntington's disease.