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Sulfite Oxidase Deficiency via the SUOX 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
SUOX 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8603SUOX81479 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

Sulfite oxidase deficiency is an inborn error in metabolism that results in the accumulation of sulfite and a reduced production of sulfate. Sulfite oxidase is the terminal enzyme in the sulfur amino acids catabolic pathway that oxidizes sulfite to sulfate. Sulfite oxidase, xanthine dehydrogenase, and aldehyde oxidase all require molybdenum as a cofactor. Therefore, this enzyme is also non-functional in molybdenum cofactor deficiencies. Patients with isolated sulfite oxidase deficiency excrete elevated levels of sulfite, thiosulfate, S-sulfocysteine, and taurine while the levels of xanthine, hypoxanthine, and uric acid are normal (Tan et al., 2005. PubMed ID: 16140720; Johnson and Duran, 2014).

Clinical presentation in isolated sulfite oxidase deficiency and molybdenum cofactor deficiencies is almost indistinguishable. Many times this disorder will be misdiagnosed as infantile encephalopathy due to the brain anomalies and neurologic symptoms. Typically, presentation will occur shortly after birth with severe convulsions that are difficult to suppress (Johnson et al., 2002. PubMed ID: 12112661; Tan et al., 2005. PubMed ID: 16140720; Johnson and Duran, 2014). Pathological studies have shown there is marked neuronal loss and demyelination in the white matter accompanied by gliosis and diffuse spongiosis. Patients with milder clinical symptoms and later onset (6-15 months) have also been reported, and in many cases an infection will trigger symptoms. Patients with molybdenum cofactor deficiency or isolated sulfite oxidase deficiency also have dysmorphic features that include long face with puffy cheeks, widely spaced eyes, elongated palpebral fissures, thick lips, a long philtrum, and a small nose, which can resemble perinatal asphyxia. Patients also present with psychomotor retardation, ophthalmologic abnormalities such as lens dislocation, peripheral hypertonicity, and axial hypotonia (Johnson et al., 2002. PubMed ID: 12112661; Johnson and Duran, 2014).


Sulfite oxidase deficiency is inherited in an autosomal recessive manner and is caused by pathogenic variants in the SUOX gene (Johnson et al., 2002. PubMed ID: 12112661; Johnson and Duran, 2014). Reported pathogenic variants include missense, nonsense, and small frameshift deletions and insertions. Many of these variants have only been reported in a single patient (Human Gene Mutation Database; Johnson and Duran, 2014). Only the Arg160Gln variant has been seen in more than one patient, and is thought be located in a mutational hotspot (Johnson and Duran, 2014).

The sulfite oxidase protein functions as a dimer and includes a heme domain, molybdenum cofactor domain, and a C-terminal domain necessary for dimerization (Kisker et al., 1997. PubMed ID: 9428520). Missense variants (Ser370Tyr, Gly473Asp) in the C-terminal domain have been shown to result in a monomeric protein with no catalytic activity. Other missense variants (Arg160Gln, Ala208Asp, Arg212Cys), occur in the catalytic active site of the enzyme (Kisker et al., 1997. PubMed ID: 9428520; Johnson and Duran, 2014).

Clinical Sensitivity - Sequencing with CNV PGxome

Clinical sensitivity cannot be estimated precisely because large cohort studies have not been conducted. However, in a small cohort of ten patients presenting clinically and biochemically with isolated sulfite oxidase deficiency, all ten patients had a molecular diagnosis (Johnson et al., 2002. PubMed ID: 12112661). Analytical sensitivity should be near 100% because all reported pathogenic variants are detectable by sequencing.

Testing Strategy

This test provides full coverage of all coding exons of the SUOX 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 a presentation similar to infantile encephalopathy and excretion of elevated levels of sulfite, thiosulfate, S-sulfocysteine, and taurine without increased levels of urinary xanthine and hypoxanthine. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in SUOX.


Official Gene Symbol OMIM ID
SUOX 606887
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Sulfite Oxidase Deficiency AR 272300


  • Human Gene Mutation Database (Bio-base).
  • Johnson and Duran, 2014. Molybdenum Cofactor Deficiency and Isolated Sulfite Oxidase Deficiency. Online Metabolic & Molecular Bases of Inherited Disease, New York, NY: McGraw-Hill.
  • Johnson et al., 2002. PubMed ID: 12112661
  • Kisker et al., 1997. PubMed ID: 9428520
  • Tan et al., 2005. PubMed ID: 16140720


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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