Test ID: NGSF9    
Hemophilia B, F9 Gene, Next-Generation Sequencing, Varies

Molecular confirmation of a clinical diagnosis of hemophilia B in affected male patients

Identification of the causative alteration in the F9 gene for prognostic and genetic counseling purposes

Helping determine hemophilia B carrier status for female patients with a family history of hemophilia B

Molecular prenatal confirmation of hemophilia B

This test detects pathogenic alterations within the F9 gene to delineate the underlying molecular defect in a patient with a laboratory diagnosis of Hemophilia B and for determining carrier status for females with a family history of hemophilia B. This test may also be used to prenatally identify and confirm hemophilia B in a male fetus at risk for inheriting the disease. Diagnostic prenatal genetic testing for female fetuses is typically medically unnecessary and not performed except in very rare cases where the fetus is known to be at risk of inheriting a pathogenic F9 alteration from both parents.

The gene target for this test is:

Gene name (transcript): F9 (GRCh37 [g19] NM_000133)

Chromosomal location: Xq27.1

This test identifies pathogenic alterations in the F9 gene associated with hemophilia B, hemophilia B Leyden, and other rare bleeding and clotting phenotypes.

This test allows for the prenatal identification of pathogenic alterations in the F9 gene associated with hemophilia B.

Prenatal genetic testing is not routinely performed without the prior identification of a familial hemophilia alteration.

Prenatal genetic testing is not routinely performed without the prior identification of a familial hemophilia alteration in an affected male relative or a female relative who is a confirmed carrier of the alteration. Requests for this prenatal testing without a known familial alteration are performed at the discretion of the Molecular Hematopathology Laboratory Director.

For any cord blood or prenatal specimen that is received, maternal cell contamination studies will be added. A maternal whole blood sample is required to perform this test.

If amniotic fluid is received, amniotic fluid culture for genetic testing will be added and charged separately. If chorionic villus specimen is received, fibroblast culture for genetic testing will be added and charged separately.

The following algorithms are available in Special Instructions:

-Hemophilia Testing Algorithm (for testing affected male patients)

-Hemophilia Carrier Testing Algorithm (for female patients with a family history of hemophilia)

• Hemophilia B Patient Information
• Informed Consent for Genetic Testing
• Hemophilia Carrier Testing Algorithm
• Hemophilia Testing Algorithm
• Informed Consent for Genetic Testing (Spanish)

Custom Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger sequencing when appropriate.