Endetyper

Endetyper is the plural form used in several Scandinavian languages for endotypes, defined as subtypes of a disease characterized by distinct underlying pathophysiological mechanisms rather than solely by clinical presentation. An endotype represents a biologically coherent subgroup within a condition, associated with specific biomarkers and often with different responses to treatment. This concept is distinct from phenotype, which describes observable traits, and from endophenotype, which refers to heritable intermediate traits linking genetics to disease.

In medicine, endotypes are used to classify heterogeneous diseases such as asthma, chronic obstructive pulmonary disease (COPD), and sepsis. For example, asthma endotypes include Type 2-high asthma, with eosinophilic inflammation driven by IL-4, IL-5, and IL-13 pathways, and Type 2-low asthma that involves non-eosinophilic mechanisms. COPD endotypes may involve eosinophilic inflammation, protease-driven tissue damage, or metabolic dysregulation. Endotypes help explain why patients with similar symptoms may respond differently to therapies.

Identification of endotypes often relies on data-driven approaches using biomarkers, omics data (genomics, transcriptomics, proteomics, metabolomics), and clinical measurements, combined with clustering or network analyses. Validation requires replication across cohorts and demonstration of differential treatment effects.

Applications include guiding precision medicine, selecting targeted therapies, predicting prognosis, and advancing research into disease mechanisms. While the term is common in research, definitions can vary and endotypes may evolve as new evidence emerges.

Etymology: from endo- meaning internal and type. See also phenotype, biomarker, precision medicine.