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xanthinuria type II (XAN2) - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

xanthinuria type II

MONDO:0011346

Also known as:XAN2XDH and AOX dual deficiencyxanthine dehydrogenase and aldehyde oxidase, combined deficiency of

Overview

Type II xanthinuria, a type of classical xanthinuria, is a rare autosomal recessive disorder of purine metabolism characterized by the deficiency of both xanthine dehydrogenase and aldehyde oxidase, leading to the formation of urinary xanthine urolithiasis and leading, in some patients, to kidney failure. Other less common manifestations include arthropathy, myopathy and duodenal ulcer, while some patients remain asymptomatic.

GeneticsAutosomal recessive · MOCOS (chr 18)

ResearchLimited published research (3 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: Xanthinuria, Increased urinary hypoxanthine level, Hyperxanthinemia, and Hypouricemia; and common findings: Myalgia. 8 total HPO annotations.

Organ System	Phenotype Count	Example Features
Kidneys and urinary system	3	Increased urinary hypoxanthine level, Reduced kidney function (renal insufficiency), Nephrolithiasis

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.

MOCOS encodes molybdenum cofactor sulfurase (888 aa). Sulfurates the molybdenum cofactor. Highest expression in Adrenal Gland (14.8 TPM) and Ovary (14.3 TPM).

Xanthinuria type II is caused by mutations in the MOCOS gene on chromosome 18.

The MOCOS protein participates in Exchange of oxygen with sulfur in MoCo pathway.

MOCOS is classified as a druggable target (Enzyme category) with score 5.5.

Diagnosis

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

Prognosis

Phenotype severity distribution: 4 always present features, 1 common feature.

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 xanthinuria type II.

3 publications have been identified in PubMed for xanthinuria type II. Research spans Review / Meta-Analysis (33%), Clinical Trial Publication (33%), and Basic Science / Preclinical (33%).

Recent Publications

Kim MM (2026). [PMID: 41641807](https://pubmed.ncbi.nlm.nih.gov/41641807/). *J Feline Med Surg*. [Review / Meta-Analysis]
Urasaki M (2025). [PMID: 41338991](https://pubmed.ncbi.nlm.nih.gov/41338991/). *Exp Anim*. [Basic Science / Preclinical]
Peng H (2025). [PMID: 41164817](https://pubmed.ncbi.nlm.nih.gov/41164817/). *Front Genet*. [Clinical Trial Publication]

Data assembled from 7 of 12 sources · Last updated Sep 20, 2026, 2:11 PM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:603592

Orphanet

European rare disease database

Orphanet:93602

GARD

Genetic and Rare Diseases Info Center

GARD:5620

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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xanthinuria type II

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Prognosis

Research Landscape

Recent Publications

Medical References

External Resources

OMIM

Orphanet

GARD

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Questions for Your Care Team

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