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Fructose-1,6-Bisphosphatase Deficiency via the FBP1 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
FBP1 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8743FBP181479 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. If the Sanger option is selected, CNV detection may be ordered through Test #600.

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

Fructose-1,6-bisphosphatase (FBPase) deficiency (OMIM #229700) is a disorder of gluconeogenesis causing life-threatening episodes of hypoglycemia and lactic acidosis. FBPase is mainly expressed in the liver and kidneys and normally catalyzes the hydrolysis of fructose 1,6 bisphosphate to fructose-6-phosphate and inorganic phosphate. When hepatic glycogen stores are depleted, gluconeogenetic precursors such as lactate, glycerol, and pyruvate are used to maintain the blood glucose level. During periods of fasting and during febrile infectious diseases, a defect in FBPase can result in hypoglycemia, ketonuria, elevated lactate and alanine levels, and metabolic acidosis. In about half of affected patients, symptoms appear in the first week after birth; in the remaining patients, symptoms mainly occur in their first years of life (Asberg et al. J Inherit Metab Dis, Epub February 2010). The deficiency can be fatal in neonates and infants, and it has been suggested that patients with FBPase deficiency have been misdiagnosed with sudden infant death syndrome or Reye’s syndrome. Tolerance to fasting generally improves with age, and the prognosis is good with avoidance of fasting and use of an emergency regimen during infections (Dixon and Leonard. Arch Dis Child 67:1387-1391, 1992).


Fructose 1,6-bisphosphatase (FBPase) is encoded by exons 1-7 of the FBP1 gene (OMIM #611570) on chromosome 9q22.2-q22.3. FBPase deficiency is an inborn error of metabolism which shows autosomal recessive inheritance. Over 20 different FBP1 variants have been reported and are thought to affect the enzyme’s ability to bind to either the substrate fructose 1,6-bisphosphate, the competitive inhibitor fructose 2,6-bisphosphate, the allosteric inhibitor AMP, or metal ions. Reported variants include nonsense variants, missense changes, small insertions and deletions leading to frameshifts or amino acid duplication, deletion of exon 1, and whole gene deletion (Herzog et al. J Inherit Metab Dis 24:87-88, 2001; Faiyaz-Ul-Haque et al. Eur J Pediatr 168:1467-1471, 2009; Asberg et al. 2010). One variant, c.960_961insG, is common in the Japanese population (Kikawa et al. Am J Hum Genet 61:852-861, 1997).

Clinical Sensitivity - Sequencing with CNV PGxome

The sensitivity of this test is currently unknown, as comprehensive assessments of sensitivity using direct sequencing methods have not been cited in the published literature for this rare disorder.

The sensitivity of duplication/deletion testing for this rare disorder is currently unknown. However, it should be noted that pathogenic gross deletions have been reported in the FBP1 gene.

Testing Strategy

This test provides full coverage of all coding exons of the FBP1 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

Candidates for this test are patients with biochemical findings or clinical symptoms consistent with fructose-1,6-bisphophatase (FBPase) deficiency. Testing is also indicated for family members of patients who have known FBP1 variants. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in FBP1.


Official Gene Symbol OMIM ID
FBP1 611570
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Fructose-Biphosphatase Deficiency AR 229700


  • Asberg, C., et.al. (2010). "Fructose 1,6-bisphosphatase deficiency: enzyme and mutation analysis performed on calcitriol-stimulated monocytes with a note on long-term prognosis." J Inherit Metab Dis. PubMed ID: 20151204
  • Dixon, M. A., Leonard, J. V. (1992). "Intercurrent illness in inborn errors of intermediary metabolism." Arch Dis Child 67(11): 1387-91. PubMed ID: 1471895
  • Faiyaz-Ul-Haque, M., et.al. (2009). "Novel FBP1 gene mutations in Arab patients with fructose-1,6-bisphosphatase deficiency." Eur J Pediatr. PubMed ID: 19259699
  • Herzog, B., et.al. (2001). "Mutation spectrum in patients with fructose-1,6-bisphosphatase deficiency." J Inherit Metab Dis 24(1): 87-8. PubMed ID: 11286391
  • Kikawa, Y., et.al. (1997). "Identification of genetic mutations in Japanese patients with fructose-1,6-bisphosphatase deficiency." Am J Hum Genet 61(4): 852-61. PubMed ID: 9382095


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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View Ordering Instructions

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2) Select Additional Test Options

No Additional Test Options are available for this test.

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