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Sitosterolemia Panel

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy Genes Gene CPT Codes Copy CPT Codes
ABCG5 81479,81479
ABCG8 81479,81479
Test Code Test Copy Genes Panel CPT Code Gene CPT Codes Copy CPT Code Base Price
10109Genes x (2)81479 81479(x4) $990 Order Options and Pricing

Pricing Comments

We are happy to accommodate requests for testing single genes in this panel or a subset of these genes. The price will remain the list price. If desired, free reflex testing to remaining genes on panel is available. Alternatively, a single gene or subset of genes can also be ordered via our Custom Panel tool.

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).

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


  • Jessica Tumolo, PhD

Clinical Features and Genetics

Clinical Features

Sitosterolemia is a disorder hallmarked by a 30-100 fold increase in plasma plant sterols. Heightened levels are due to defects in the adenosine triphosphate-binding cassette transporter protein which effluxes free sterols from hepatocytes and enterocytes into the gut lumen. The primary clinical features of sitosterolemia are tendon or tuberous xanthomas and accelerated atherosclerosis, which have been report in individuals as young as 4 years of age (Mymin et al. 2003). Hemolytic anemia, stomatocytes formation, and macrothrombocytopenia are common hematologic findings and may be the only clinically observed symptom in patients (Wang et al. 2014; Escolà-Gil et al. 2014). Clinical colormetric enzyme assays to quantify sterols cannot discriminate between cholesterol and plant sterols making diagnosis difficult (Kidambi and Patel 2008). Genetic testing is helpful in the differential diagnosis of sitosterolemia from cerebrotendinous xanthomatosis, cardiovascular disease, and familial hypercholesterolemia. Ezetimibe, an inhibitor of intestinal cholesterol absorption, has been shown to be effective in reducing plasma sterol levels (Othman et al. 2015).


Sitosterolemia is inherited in an autosomal recessive manner with pathogenic variants in the ABCG5 and ABCG8 genes being responsible for 1/3 and 2/3 of cases respectively (Lee et al 2001; Escolá-Gil et al. 2014; Hubacek et al. 2001). The ABCG5 and ABCG8 genes encode the heterodimer adenosine triphosphate-binding cassette transporter protein present on enterocytes and hepatocytes. In enterocytes, the transporter is located on the apical membrane and promotes efflux of plant sterols back into the intestinal lumen. In the liver, the transporter is responsible for excretion of plant sterols into the bile (Lee et al. 2001). Pathogenic variants in the ABCG5 and ABCG8 genes impair transporter function or surface expression and result in elevated plasma plant sterol levels.

Loss of function pathogenic variants are most commonly found in the ABCG5 gene and include nonsense, frameshift, splice site alterations and gross deletions of exon 3. Missense variants, primarily occurring in exon 9, have also been reported to be causative for sitosterolemia (Lee et al. 2001; Escolá-Gil et al. 2014; Lu et al. 2001). ABCG5 pathogenic variants are more commonly found in patients of Chinese, Japanese, or Indian decent (Kidambi and Patel 2008).

Clinical Sensitivity - Sequencing with CNV PGxome

To date, only about 100 cases of sitosterolemia have been reported (Escolá-Gil et al. 2014). In a series of 25 unrelated families with a diagnosis of sitosterolemia based on elevated plasma sitosterol levels, pathogenic variants in the ABCG5 and ABCG8 genes were found in 9 of 25 and 16 of 25 families respectively (Lu et al. 2001). Analytical sensitivity for detection of pathogenic variants in the ABCG5 and ABCG8 genes is >95%. Two cases of a deletion of exon 3 in the ABCG5 gene have been reported that are not predicted to be detected by sequencing (Lu et al. 2001).

Testing Strategy

This test is performed using Next-Gen sequencing with additional Sanger sequencing as necessary.

This panel provides 100% coverage of all coding exons of the genes 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 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

Candidates for testing include patients presenting with xanthomas, premature atherosclerosis, hemolytic anemia, and macrothrombocytopenia. Presence of stomatocytes in bloods smears and elevated plant sterol levels (>20-30mg/dl) are common laboratory findings. Gas chromatography or high performance liquid chromatography are necessary to specifically measure plant sterol levels as colormetric assays to measure sterols do not differentiate between cholesterol and plant sterols (Kidambi and Patel 2008; Lu et al. 2001).


Official Gene Symbol OMIM ID
ABCG5 605459
ABCG8 605460
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Sitosterolemia AR 210250

Related Test



  • Escolà-Gil J.C. et al. 2014. Current Atherosclerosis Reports. 16: 424. PubMed ID: 24821603
  • Hubacek J.A. et al. 2001. Human Mutation. 18: 359-60. PubMed ID: 11668628
  • Kidambi S., Patel S.B. 2008. Journal of Clinical Pathology. 61: 588-94. PubMed ID: 18441155
  • Lee M.H. et al. 2001. Nature Genetics. 27: 79-83. PubMed ID: 11138003
  • Lu K. et al. 2001. American Journal of Human Genetics. 69: 278-90. PubMed ID: 11452359
  • Mymin D. et al. 2003. Circulation. 107: 791. PubMed ID: 12578886
  • Othman R.A. et al. 2015. The Journal of Pediatrics. 166: 125-31. PubMed ID: 25444527
  • Wang Z. et al. 2014. American Journal of Hematology. 89: 320-4.  PubMed ID: 24166850


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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