| Comparative Coagulation |
|
|
|
Testing Services - Hemophilia
B in German Wirehaired Pointers
|
| |
| Hemophilia B was first diagnosed in a Drahthaar in the United States
in 1989. Since that time, approximately 20 affected males have been
identified in the United States and Canada. The defect spans more
than seven generations and can be traced back to dogs born and bred
in Germany. The propagation of Hemophilia B in North America has been
prevented, for the most part, by screening males to confirm they have
normal coagulation Factor IX values. Carrier females, however, often
have normal Factor IX values and cannot be directly diagnosed using
Factor IX assays. Through research at Cornell's Comparative Coagulation
Laboratory and the James A. Baker Institute, a new screening test
has been developed to accurately identify Hemophilia B carrier females. |
| |
| |
DNA Analyses for Hemophilia B Carrier Detection: |
 |
| Carrier detection is based on a direct DNA test.
DNA is isolated from a blood sample and a specific portion of the
Factor IX gene is then amplified and scored to detect the presence
(or absence) of a unique Factor IX mutation. Hemophilia B carrier
females have one copy of the mutant sequence and one copy of the normal
Factor IX gene sequence. Clear females have two copies of the normal
Factor IX gene sequence. DNA analysis can differentiate affected males
from clear males, however coagulation Factor IX assays can accurately
(and more rapidly) define a male's genetic status. |
| |
| |
|
Summary of Research Findings: |
|
| The carrier detection test is based on results of
research sponsored initially by the VDD-Group North America and later
funded by The Morris Animal Foundation. The cooperation and participation
of more than twenty owners and breeders were crucial for the project's
success. In this study, DNA was isolated from clear and Hemophilia
B affected males and the Factor IX gene sequence was compared. Aberrant
DNA sequence, referred to as an "insertion mutation" was
found in the hemophilic males' Factor IX gene. The gene insertion
appears to impair Factor IX protein production. A screening test to
detect this mutation was developed, based on amplification of a specific
portion of the Factor IX gene. Using this screening test, the Factor
IX mutation was found exclusively in affected males and obligate carrier
females, and was confirmed to segregate (or track) with Hemophilia
B through a 5-generation pedigree. A complete description of this
study is published in Mammalian Genome 2003;14:788-795. |
| |
| |
|
Screening to Prevent Propagation of Hemophilia B: |
|
Males: |
- Coagulation Factor IX assays are rapid and accurate screening
tests for Hemophilia B in males. Males having normal Factor IX
activities (> 50%) are not at risk for expressing or transmitting
Hemophilia B. Males affected with Hemophilia B should not be used
for breeding.
|
|
Females: |
- All dams and daughters of hemophilic males are obligate carriers.
Each daughter of a carrier dam has a 50% chance of being a carrier.
The mutation detection test for Hemophilia B provides a specific
means for determining whether a suspect or unknown status female
is a carrier of Hemophilia B. Carrier females can be safely spayed,
with no risk of abnormal bleeding due to Factor IX deficiency.
|
| |
| |
|
Testing Information: |
|
|
We now offer a direct DNA test for Hemophilia B carrier detection
in German wirehaired pointers, a breed also known as Deutsch Drahthaar.
This test identifies the presence (or absence) of a specific Factor
IX mutation associated with Hemophilia B in this breed. This test
is ONLY valid for Hemophilia B in German Wirehaired Ponters. |
|
Sample Requirements |
Submit 3.0 to 4.0 ml of EDTA whole blood (purple top tube), shipped
on cold packs for overnight delivery. Do not freeze whole blood.-
Registered name, number, and pedigree must be included with each
submission.
|
|
Turnaround time for the DNA test is 1 to 2 weeks |
|
Cost per test is $100.00 |
| |
| |
|
FAQs |
|
|
See the FAQ page on Hemophilia B. Group
members should feel free to call the Coagulation Laboratory (607-275-0622)
for any questions on Hemophilia B or other hereditary bleeding disorders. |
| |
