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Fanconi Anemia via the FANCB 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
FANCB 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
7055FANCB81479 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.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Siwu Peng, PhD

Clinical Features and Genetics

Clinical Features

Fanconi Anemia (FA) is an inherited anemia associated with bone marrow failure (aplastic anemia), however, the clinical features of FA can expand well beyond hematologic anomalies. FA is also characterized by a range of physical abnormalities, pancytopenia, and predisposition to certain cancers - particularly acute myelogenous leukemia (AML), gynecologic and GI tract cancers, and cancers of the head and neck (Auerbach. 2009. PubMed ID: 19622403). FA patients are up to 800 fold more susceptible to AML than the general population with a median age of onset of 13 years (Rosenberg et al. 2003. PubMed ID: 12393424). Physical abnormalities include radial ray defects (absent thumb or radius), skin pigmentation defects, short stature, microphthalmia, renal and urinary tract defects, genital defects (males in particular), gastrointestinal malformations (atresia), congenital heart disease, hearing and central nervous system defects, and general developmental delay (Tischkowitz and Hodgson. 2003. PubMed ID: 12525534; Dokal. 2000. PubMed ID: 11030042). About one-third of FA patients have no obvious physical abnormalities and are diagnosed only after a family member is diagnosed, or after developing hematologic anomalies such as thromobocytopenia, leukopenia, and anemia (Giampietro et al. 1997. PubMed ID: 8986277).

A hallmark of FA is hypersensitivity of chromosomes to inter cross-strand linkage (ICL) agents such as diepoxybutane (DEB) or mitomycin C (MMC) (Sasaki and Tonomura. 1973. PubMed ID: 4352739). Exposure of primary cell cultures from FA patients to DEB or MMC results in chromosomal aberrations (breaks, radials, rearrangements) due to damaged DNA repair mechanisms that require functional products of the Fanconi anemia genes. For example, the FANCA, -B, -C, -E, -F, -G, -L, and -M proteins are part of a nuclear core complex that regulates monoubiquitination of the FANCD2 and FANCI proteins (ID complex) during S-phase and after exposure to DNA crosslinking agents (Moldovan and D'Andrea. 2009. PubMed ID: 19686080). In unaffected individuals, ubiquitination helps localize the ID complex to sites of DNA damage and facilitate repair, but in FA patients, this mechanism is impaired (Grompe and van de Vrugt. 2007. PubMed ID: 17488615; Smogorzewska et al. 2007. PubMed ID: 17412408).

Genetics

FA is a genetically heterogeneous disorder. To date, 22 FA or FA-like genes have been discovered. Inheritance is primarily autosomal recessive or X-linked, however a case of heterozygous FA-like syndrome was associated with a dominant-negative variant in the RAD51 (FANCR) gene (Ameziane et al. 2015. PubMed ID: 26681308). Approximately 86% of all cases are attributed to variants in three genes: FANCA (~ 60%), FANCC (~ 16%), and FANCG (~ 10%) (Auerbach. 2009. PubMed ID: 19622403). Since variants in FANCA are the most common cause of FA, it is important to note that large deletions make up over one-third of all reported pathogenic variants in FANCA. In the United States, the carrier frequency for Fanconi anemia is estimated at 1 in 181, and the incidence rate is estimated at 1 in 131,000 (http://www.fanconi.org/; Rosenberg et al. 2011. PubMed ID: 21739583). Nearly 95% of all FA cases are attributed to variants in eight genes, FANCA, -C, -G, -D1 (aka BRCA2), -D2, -E, -F, and –L that are either part of the core complex required for ID complex ubiquitination and facilitation of DNA repair or function directly in ICL recognition and repair (Grompe and van de Vrugt. 2007. PubMed ID: 17488615). FA is phenotypically diverse even among related patients that harbor the same variants; null alleles however are reported to result in more severe phenotypes (Faivre et al. 2000. PubMed ID: 11110674). FA affects males and females roughly equally and affects all ethnic groups.

To date, over 20 unique causative variants have been reported throughout the FANCB gene comprising primarily missense variants and variants that result in premature protein termination such as nonsense variants, small frameshift deletions, or splice-site variants. At least 3 large deletions and one large duplication involving one or more exons of the FANCB gene have been reported in patients with FA (www.rockefeller.edu/fanconi/mutate/; Umana et al. 2011. PubMed ID: 22052692; Meetei et al. 2004. PubMed ID: 15502827; McCauley et al. 2011. PubMed ID: 2190217). FANCB is located on the X-chromosome. Males who inherit pathogenic variants in the FANCB gene will be affected; female carriers usually have no FA phenotype. Variants in FANCB account for ~ 2% of FA cases and are associated with VACTERL (vertebral, anal, cardiac, trachea-esophageal fistula, renal, and limb anomalies) (Umana et al. 2011. PubMed ID: 22052692; Meetei et al. 2004. PubMed ID: 15502827; McCauley et al. 2011. PubMed ID: 2190217).

Clinical Sensitivity - Sequencing with CNV PGxome

Pathogenic variants in the FANCB gene account for ~ 2% of all Fanconi anemia cases (Mehta and Tolar. 2018. PubMed ID: 20301575).

Several gross deletions and one duplication involving one or more exons have been reported for the FANCB gene (The Rockefeller University Fanconi Anemia Mutation Database; Human Gene Mutation Database).

Testing Strategy

This test provides full coverage of all coding exons of the FANCB 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 clinical features of FA, individuals with a family history of FA, and patients that develop aplastic anemia and hematologic disorders at any age even if they present no other physical abnormalities.

Gene

Official Gene Symbol OMIM ID
FANCB 300515
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Fanconi Anemia, Complementation Group B XL 300514

Related Test

Name
Fanconi Anemia via the FANCG Gene

Citations

  • Ameziane et al. 2015. PubMed ID: 26681308
  • Auerbach. 2009. PubMed ID: 19622403
  • Dokal. 2000. PubMed ID: 11030042
  • Faivre et al. 2000. PubMed ID: 11110674
  • Fanconi Anemia Research Fund, Inc.
  • Giampietro et al. 1997. PubMed ID: 8986277
  • Grompe and van de Vrught. 2007. PubMed ID: 17488615
  • Human Gene Mutation Database (Bio-base).
  • McCauley et al. 2011. PubMed ID: 21910217
  • Meetei et al. 2004. PubMed ID: 15502827
  • Mehta and Tolar. 2018. PubMed ID: 20301575
  • Moldovan and D’Andrea. 2009. PubMed ID: 19686080
  • Rosenberg et al. 2003. PubMed ID: 12393424
  • Rosenberg et al. 2011. PubMed ID: 21739583
  • Sasaki and Tonomura. 1973. PubMed ID: 4352739
  • Smogorzewska et al. 2007. PubMed ID: 17412408
  • The Rockefeller University Fanconi Anemia Mutation Database.
  • Tischkowitz and Hodgson. 2003. PubMed ID: 12525534
  • Umana et al. 2011. PubMed ID: 22052692

Ordering/Specimens

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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ORDER OPTIONS

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2) Select Additional Test Options

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