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Xanthinuria Type II via the MOCOS Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
MOCOS 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8063MOCOS81479 81479,81479 $990 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing platform).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing platform).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

Turnaround Time

3 weeks on average for standard orders or 2 weeks on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.


Genetic Counselors


  • McKenna Kyriss, PhD

Clinical Features and Genetics

Clinical Features

Xanthinuria type II is an inherited metabolic disorder characterized by the deficiency of both of the molybdenum-cofactor requiring enzymes xanthine dehydrogenase and aldehyde oxidase (Mendel, 2009. PubMed ID: 19623604; Raivio et al., 2014). Biochemically, patients have greatly elevated serum and urinary xanthine, elevated serum and urinary hypoxanthine, and hypouricemia. The majority of patients may be asymptomatic, although roughly one-third of patients may present with urinary tract xanthine calculi that may lead to hematuria, crystalluria, renal colic or acute renal failure. Myositis is also sometimes observed (Raivio et al., 2014; Ceballos-Picot and Jinnah, 2016). Xanthinuria Type II is characterized by deficiency in xanthine dehydrogenase and aldehyde oxidase due to pathogenic variants in the molybdenum cofactor sulfurase, MOCOS, gene. Although the two types have similar clinical presentation, a distinction between the two types is based on the ability to oxidize allopurinol to oxypurinol (Raivio et al., 2014).


Xanthinuria Type II is a rare autosomal recessive disorder caused by pathogenic variants in the MOCOS gene located on chromosome 18 at 18q12.2. Although clinical reports indicate that types I and II are roughly equal in incidence, only a handful of type II patients have been molecularly diagnosed (Raivio et al., 2014). Reported pathogenic variants in MOCOS include missense, nonsense, and small frameshifts (Ichida et al., 2001. PubMed ID: 11302742; Yamamoto et al., 2003. PubMed ID: 14624414; Peretz et al., 2007. PubMed ID: 17368066; Zhou et al., 2015. PubMed ID: 25967871). Incidence estimates for xanthinuria types I and II range from 1 in 6,000 to 1 in 69,000 (Harkness et al., 1983. PubMed ID: 6422142; Harkness et al., 1986. PubMed ID: 3104682; Raivio et al., 2014). This large range may reflect the rarity of the disease and population differences. Xanthinuria may be more prevalent in Mediterranean countries (Raivio et al., 2014).

The MOCOS gene encodes molybdenum cofactor sulfurase, which is required for resulfuration of the molybdenum synthase enzyme during biosynthesis of the molybdenum cofactor molybdopterin (Johnson and Duran, 2014).

Clinical Sensitivity - Sequencing with CNV PGxome

Clinical sensitivity cannot be estimated because only a small number of patients have been reported. Analytical sensitivity should be high because the great majority of pathogenic variants reported are detectable by sequencing.

Testing Strategy

This test provides full coverage of all coding exons of the MOCOS gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).

Indications for Test

Patients with biochemical and/or clinical features consistent with xanthinuria type II, such as xanthinuria, hypoxanthinuria, hypouricemia, and possibly kidney stones, are good candidates for this test. Family members of patients who have known MOCOS pathogenic variants are also good candidates. We will also sequence the MOCOS gene to determine carrier status.


Official Gene Symbol OMIM ID
MOCOS 613274
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Xanthinuria, Type II AR 603592


  • Ceballos-Picot and Jinnah, 2016. Disorders of Purine Metabolism Affecting Adults. In: Hollak C.E.M. and Lachmann R.H., editors. Inherited Metabolic Disease in Adults: A Clinical Guide. New York: Oxford University Press, p 251-.263.
  • Harkness et al., 1983. PubMed ID: 6422142
  • Harkness et al., 1986. PubMed ID: 3104682
  • Ichida et al., 2001. PubMed ID: 11302742
  • Johnson and Duran, 2014. Molybdenum Cofactor Deficiency and Isolated Sulfite Oxidase Deficiency. Online Metabolic & Molecular Bases of Inherited Disease, New York, NY: McGraw-Hill.
  • Mendel, 2009. PubMed ID: 19623604
  • Peretz et al., 2007. PubMed ID: 17368066
  • Raivio et al., 2014. Xanthine Oxidoreductase—Role in Human Pathophysiology and in Hereditary Xanthinuria. The Online Metabolic and Molecular Bases of Inherited Disease, New York, NY: The McGraw-Hill Companies, Inc.
  • Yamamoto et al., 2003. PubMed ID: 14624414
  • Zhou et al., 2015. PubMed ID: 25967871


Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page

If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.

Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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Note: acceptable specimen types are whole blood and DNA from whole blood only.
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