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methemoglobinemia type 4 - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

methemoglobinemia type 4

MONDO:0009605

Also known as:CYB5A methemoglobinemiamethemoglobinemia caused by mutation in CYB5AMETAG

Overview

Any methemoglobinemia in which the cause of the disease is a mutation in the CYB5A gene.

GeneticsAutosomal recessive · CYB5A (chr 18)

ResearchLimited published research (9 articles)

Clinical Presentation

Built from Human Phenotype Ontology (HPO) phenotype annotations and GeneReviews clinical descriptions. Features represent findings documented across known cases — not an exhaustive list of possible symptoms.

Features include always present findings: Ambiguous genitalia, Elevated circulating luteinizing hormone level, Methemoglobinemia, and Bifid scrotum and others. 10 total HPO annotations.

Organ System	Phenotype Count	Example Features
Lab test results	1	Elevated circulating luteinizing hormone level

Explore clinical features

Genetic Landscape

Assembled from HGNC gene records, ClinGen gene-disease validity evidence, and ClinVar pathogenic variant data. Validity classifications reflect the strength of published evidence linking each gene to this disease.

CYB5A encodes cytochrome b5 type A (134 aa). Cytochrome b5 is a membrane-bound hemoprotein functioning as an electron carrier for several membrane-bound oxygenases Highest expression in Liver (181.4 TPM) and Lung (87.3 TPM).

Methemoglobinemia type 4 is caused by mutations in the CYB5A gene on chromosome 18.

The CYB5A protein participates in CYB5R3:FAD reduces CYB5A:ferriheme to CYB5A:heme and CYB5A:heme reduces Asc.- to AscH- pathways.

CYB5A is classified as a druggable target with score 10.4.

Diagnosis

Genetic testing for CYB5A is available. Testing is considered confirmatory for diagnosis.

Prognosis

Phenotype severity distribution: 6 always present features.

Research Landscape

Sourced from ClinicalTrials.gov and PubMed. Publication types are classified using NLM-curated article metadata; research type breakdowns reflect the nature of published work for this disease.

No clinical trials have been registered for methemoglobinemia type 4.

9 publications have been identified in PubMed for methemoglobinemia type 4. Research spans Review / Meta-Analysis (44%), Case Report / Case Series (33%), and Clinical Trial Publication (11%).

Recent Publications

Ogo T (2026). [PMID: 41866186](https://pubmed.ncbi.nlm.nih.gov/41866186/). *Circulation journal : official journal of the Japanese Circulation Society*. [Clinical Trial Publication]
Barzani HAH (2026). [PMID: 41773699](https://pubmed.ncbi.nlm.nih.gov/41773699/). *Critical reviews in analytical chemistry*. [Review / Meta-Analysis]
Chai Q (2025). [PMID: 40381133](https://pubmed.ncbi.nlm.nih.gov/40381133/). *Journal of assisted reproduction and genetics*. [Review / Meta-Analysis]
Szuber N (2025). [PMID: 41347984](https://pubmed.ncbi.nlm.nih.gov/41347984/). *Hematology. American Society of Hematology. Education Program*. [Review / Meta-Analysis]
He KY (2025). [PMID: 39154701](https://pubmed.ncbi.nlm.nih.gov/39154701/). *Clinica chimica acta; international journal of clinical chemistry*. [Case Report / Case Series]

Data assembled from 6 of 12 sources · Last updated Sep 18, 2026, 1:02 PM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:250790

GARD

Genetic and Rare Diseases Info Center

GARD:15196

Questions for Your Care Team

→Should my partner and I meet with a genetic counselor to discuss carrier status and family planning?
→Are there specialists or centers of excellence for this condition in my area?
→Is there a patient registry I should consider joining?

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methemoglobinemia type 4

Overview

Clinical Presentation

Explore clinical features

Genetic Landscape

Diagnosis

Prognosis

Research Landscape

Recent Publications

Medical References

External Resources

OMIM

GARD

Related Diseases

Questions for Your Care Team

Questions for Your Care Team