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).

Reference for mutation databases:

F9 variant database, CHBMP

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 3-10cc 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:
Bloodworks Northwest
Eastlake SDL
1551 Eastlake Ave E.
Seattle, WA 98102

Send cultured amniocyte samples to:
Bloodworks Northwest
Genomics Testing Laboratory
921 Terry Ave
Seattle, WA 98104

For additional information, please see Ordering Information-Bleeding Disorders

Requisition Form Request for Testing Eastlake Bleeding Disorders Laboratory
Transaction Code 3250-10
CPT Codes 81405
Turn around Time (analytic time) 5-10 business days
Report/Results Fax number required to receive report

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