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IEMbase 0204: HJV-related hemojuvelin deficiency

Scope

Field Value
IEMbase ID 204
Nosology 22.2.02.01
Gene HJV
External IDs OMIM:602390; ORPHA:79230
Generated mapping CANDIDATE; Hemochromatosis.yaml
Candidate DisMech targets Hemochromatosis.yaml#Type 2A
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as HJV-related hemojuvelin deficiency, with alternate labels hereditary hemochromatosis type 2A and HFE2A. Treatability is marked yes.

The biochemical rows include increased ferritin, variable glucose, increased liver iron, and increased transferrin saturation. Characteristic clinical rows include arthralgia, cardiomyopathy, fatigue, hepatopathy, hypogonadism, and liver cirrhosis. Treatment rows list iron chelation and phlebotomy, both decreasing serum iron.

DisMech phenotype coverage

Hemochromatosis.yaml#Type 2A is the correct target. The local entry explicitly defines Type 2A as HJV-related juvenile hemochromatosis caused by biallelic HJV pathogenic variants. It covers the non-HFE hepcidin-deficiency mechanism, early/severe systemic iron overload, high transferrin saturation, elevated ferritin, liver disease, cirrhosis, cardiomyopathy, diabetes/hyperglycemia, hypogonadotropic hypogonadism, arthropathy, fatigue, abdominal pain, and iron removal by phlebotomy or chelation.

Concordance and completeness

Judgement: accept generated candidate as correct, with subtype resolution to Hemochromatosis.yaml#Type 2A.

IEMbase and DisMech agree on HJV/type 2A juvenile hemochromatosis identity, iron-overload biomarkers, hepatic disease, cardiomyopathy, endocrine disease, arthralgia, phlebotomy, and chelation. IEMbase adds concise HJV-specific liver iron and hepatopathy rows. DisMech is richer for the shared hepcidin pathway, subtype differentiation, evidence, penetrance and modifier framing, and treatment rationale.

Curation actions

  • Treat this as covered by Hemochromatosis.yaml#Type 2A, not only the file level.
  • Consider adding liver iron as a structured readout if the hemochromatosis biochemical section is expanded.
  • No standalone HJV entry is required unless future curation chooses to split juvenile hemochromatosis subtypes into separate disease files.