Each column keeps its native condition scope. Initial features are displayed alphabetically, not ranked by clinical importance. Counts remain separate, and an empty cell does not mean a feature cannot occur.
"},"coverage":{"countRecords":1,"emptyColumnKeys":[],"hpoRelease":"2026-06-23","narrativeSourceChanges":[],"records":1,"sourceGroups":{"omim":0,"orphanet":0,"published":1}},"features":[{"hpoId":"HP:0034253","label":"Eosinophil nuclear hypersegmentation","primary":false}],"ledeHtml":"Eosinophil peroxidase deficiency is a condition that affects certain white blood cells called eosinophils but causes no health problems in affected individuals. Eosinophils aid in the body's immune response. During a normal immune response, these cells are turned on (activated), and they travel to the area of injury or inflammation. The cells then release proteins and other compounds that have a toxic effect on severely damaged cells or invading organisms. One of these proteins is called eosinophil peroxidase. In eosinophil peroxidase deficiency, eosinophils have little or no eosinophil peroxidase. A lack of this protein does not seem to affect the eosinophils' ability to carry out an immune response.","mondoId":"MONDO:0043364","records":[{"frequencyKind":"count","key":"4eb2f778ccb24695eab1be365bb3c27e7d35559aac38a881590e07e957990845","raw":{"aspect":"P","body_system":"blood","disease_id":"OMIM:261500","disease_name":"Eosinophil peroxidase deficiency","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0034253","is_excluded":false,"label":"Eosinophil nuclear hypersegmentation","onset_id":null,"reference":"PMID:7809065","source_release":"2026-06-23"},"sourceGroups":["published"]}],"referenceLabels":{},"references":{"causeHtml":"","identityNote":"MONDO cross-references identify native condition entries. Ancestor membership does not transfer phenotype values between groups.","importantHtml":""},"sections":[{"bodyHtml":"Mutations in the EPX gene cause eosinophil peroxidase deficiency. The EPX gene provides instructions for making the eosinophil peroxidase protein. During an immune response, activated eosinophils release eosinophil peroxidase at the site of injury. This protein helps form molecules that are highly toxic to bacteria and parasites. These toxic molecules also play a role in regulating inflammation by fighting microbial invaders.
EPX gene mutations reduce or prevent eosinophil peroxidase production or result in a protein that is unstable and nonfunctional. As a result, eosinophils have severely reduced amounts of eosinophil peroxidase or none at all. Other proteins within affected eosinophils are normal, and while the cells lacking eosinophil peroxidase are smaller and may have structural changes, the loss of eosinophil peroxidase does not appear to impair the function of eosinophils.
","key":"forms","title":"What causes Eosinophil peroxidase deficiency?"},{"bodyHtml":"Because eosinophil peroxidase deficiency does not cause any health problems, this condition is often diagnosed when blood tests are done for other reasons or when a family member has been diagnosed with the condition.
Source: MedlinePlus Genetics
","key":"overview","title":"Condition overview"}],"sharedSources":[],"slug":"eosinophil-peroxidase-deficiency","sourceDocuments":[{"name":"Eosinophil peroxidase deficiency","reviewed":"2014-12","sections":{"causes":{"fetchedAt":"2026-10-20T20:21:11.193917+00:00","label":"Causes","pageSha256":"49efbd45104722c0d9067d4ab752d223770116c6918846763e7d4af50d2f5d2f","sourceUrl":"https://medlineplus.gov/genetics/condition/eosinophil-peroxidase-deficiency/#causes","status":"available"}},"source_release":"2026-10-01","url":"https://medlineplus.gov/genetics/condition/eosinophil-peroxidase-deficiency"}],"sourceNote":"MedlinePlus descriptions and Causes; original HPO annotations.","takeawayHtml":"Cause explanations are from MedlinePlus Genetics. Feature values below retain their original sources and patient groups.","title":"Eosinophil peroxidase deficiency"},"schemaVersion":1}