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Hemophilia B via the F9 Gene

Summary and Pricing

Test Method

Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
7641 F9 81238 81238,81479 $640 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
7641F981238 81238,81479 $640 Order Options and Pricing

Pricing Comments

This test is also offered via our exome backbone with CNV detection (click here). The exome-based test may be higher priced, but permits reflex to the entire exome or to any other set of clinically relevant genes.

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

Turnaround Time

18 days on average for standard orders or 13 days 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

Hemophilia B, also known as factor IX deficiency or Christmas disease, is the second most common type of hemophilia occurring in about one in 25,000 males. Symptoms range widely, but mainly include prolonged bleeding following dental or surgical procedures, excessive bruising, prolonged nose bleeding, deep muscle hematomas, hemarthrosis and GI bleeding (Konkle et al. 2011). Disease severity (mild, moderate, or severe) and age of diagnosis are related to the level of Factor IX clotting activity. Individuals with mild hemophilia B are often not diagnosed until later in life after abnormal bleeding occurs following trauma. Individuals with severe forms are typically diagnosed before age two and average several bleeding episodes per month. Treatment with recombinant factor IX or tranexamic acid may help promote clotting and are often used for patients undergoing surgery (Lambert et al. 2007).

Genetics

Hemophilia B is an X-linked recessive disorder characterized by mutations in the F9 gene. Males are primarily affected, but homozygous females with F9 mutations have also been documented. To date, over a thousand unique variants have been observed throughout the F9 gene with missense mutations being causative in about 75% of cases (Giannelli et al. 1998). In about 30% of cases, there is no family history of the disorder and the condition is a result of a de novo gene mutation. Mutations in the F9 promoter are associated with a specific subtype, known as hemophilia B Leyden. These individuals express low levels of F9 protein until puberty at which point F9 levels rise with increased androgen receptor and growth factor activity (Funnell et al. 2013). Factor IX is a zymogen present in the plasma. When cleaved and activated by factor Xla or factor VIIa it hydrolyzes factor X to drive coagulation.

Clinical Sensitivity - Sequencing with CNV PG-Select

Clinically, Hemophilia A is not distinguishable from Hemophilia B. With appropriate biochemical testing indicative of Hemophilia B (Factor IX activity <30%), detection of causative F9 mutations are found via DNA sequencing in ~95% of cases.

Testing Strategy

This test provides full coverage of all coding exons of the F9 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.

Indications for Test

This test is for individuals with symptoms and assays of hemostasis (prolonged PPT, low Factor IX levels) that suggest Hemophilia B. Female carrier status cannot be definitively diagnosed by coagulation testing. Most patients have a positive family history. Males are predominant candidates as the disease is X-linked.

Gene

Official Gene Symbol OMIM ID
F9 300746
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Hereditary Factor IX Deficiency Disease XL 306900

Related Tests

Name
Bleeding Disorders Panel
Coagulation Factor Deficiency Panel

Citations

  • Funnell APW, Wilson MD, Ballester B, Mak KS, Burdach J, Magan N, Pearson RCM, Lemaigre FP, Stowell KM, Odom DT, Flicek P, Crossley M. 2013. A CpG Mutational Hotspot in a ONECUT Binding Site Accounts for the Prevalent Variant of Hemophilia B Leyden. Am. J. Hum. Genet. 92: 460–467. PubMed ID: 23472758
  • Giannelli F, Green PM, Sommer SS, Poon M, Ludwig M, Schwaab R, Reitsma PH, Goossens M, Yoshioka A, Figueiredo MS, Brownlee GG. 1998. Haemophilia B: database of point mutations and short additions and deletions--eighth edition. Nucleic Acids Res. 26: 265–268. PubMed ID: 9399849
  • Konkle BA, Josephson NC, Nakaya Fletcher SM, Thompson AR. 2011. Hemophilia B. In: Pagon RA, Adam MP, Bird TD, Dolan CR, Fong C-T, and Stephens K, editors. GeneReviewsTM, Seattle (WA): University of Washington, Seattle. PubMed ID: 20301668
  • Lambert T, Recht M, Valentino LA, Powell JS, Udata C, Sullivan ST, Roth DA. 2007. Reformulated BeneFix: efficacy and safety in previously treated patients with moderately severe to severe haemophilia B. Haemoph. Off. J. World Fed. Hemoph. 13: 233–243. PubMed ID: 17498071

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


Specimen Types

Specimen Requirements and Shipping Details

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ORDER OPTIONS

View Ordering Instructions

1) Select Test Method (Backbone)


1) Select Test Type


2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

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