DNA Hemophilia B Mutation Screen
|Also Known as (Alias)||HemB Genotyping; F9 Genotyping|
|Method||Polymerase Chain Reaction (PCR) Based|
|Test Information||Analysis of the Factor IX gene (Hemophilia B) is performed by direct sequence analysis of exons 1 – 8 and one common recurrent 3′ ut region genotype. The Genomics Testing Laboratory has had a high level of success in locating the mutation within these areas (Weinmann et al, BJ Haematol 100: 58, 1998). A reference for the DNA FIX mutation database can be found at http://www.factorix.org/, and http://www.cdc.gov/ncbddd/medical-services/wa-center-for-bleeding-disorders/champs.html.
If the specific mutation cannot be identified, intragenic linkage is often useful to trace the affected allele through the family tree by following 4 polymorphic sites. Linkage studies also help identify the de novo origin of mutations in families with an isolated occurrence (eg maternal grandparents). Intragenic linkage may be useful in 80-90% of families where key family members (patient and both parents of potential carrier) are available.
|Additional Test Information||Sequencing is performed for exons 1-8 and the 3′ ut region. Confirmation is performed one of two ways. If the mutation creates/removes a restriction enzyme digestion site, the testing will be performed by RFLP. If a restriction enzyme digestion site is not present, testing will be done by sequencing the exon in which the mutation is located.|
|Sample Requirements||EDTA (lavender top)|
|Requested Volume||5-10cc EDTA (lavender top) tube OR
Analysis of amniocytes can be performed on cultured amniocytes. Two T-25 flasks of cells cultured to confluency will be accepted. Bloodworks Northwest does not have facilities to culture amniocytes.
|Shipping Information||Whole blood shipped at 4oC or ambient temperature is acceptable and should arrive in the lab within 48 hours.
Send samples to:
For additional information, please see Ordering Information-Bleeding Disorders
|Requisition Form||Request for Testing Hemostasis Reference Laboratory|
|Turn around Time (analytic time)||5-10 business days|
|Report/Results||Fax number required to receive report|