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Haemophilia A Genetic Test
Short Description : Haemophilia A genetic testing
Also known as : [Factor VIII Genetic Test],[FVIII Genetic Test]


DNA/RNA
Test performed by: LabPLUS - Dept. Diagnostic Genetics - Molecular Haematology


Specimen Collection

NOTE:

  1. All samples referred for Haemophilia A genetic testing must be accompanied with information regarding the inheritance of this trait in the patient's family.
  2. All prenatal samples referred for Haemophilia A genetic testing must be accompanied by maternal bloods for DNA extraction (collection details as below). 
  3. Prior work-up of the mutation within the relevant family is preferable before refering prenatal samples for analysis.

Note: All samples should be forwarded to LabPlus at room temperature within 24hours.


CPD9 mL CPD Blood (Preferred)
EDTA9 mL EDTA Blood
Prenatal Amniotic Fluid
Prenatal Chorionic Villus
Turnaround Time: Within 4 weeks
Diagnostic Use and Interpretation

This test is used to establish the genetic basis of haemophilia A. These results are useful for the confirmation of haemophilia A and in prenatal and carrier studies of haemophilia A.

For information about Haemophilia B genetic testing:

Haemophilia B genetic testing


Contact Information

To contact the Molecular Haematology team please call:

Auckland City Hospital   (09) 307 4949
Lablink   ext 22000
Prof. Peter Browett (Haematologist)     ext 9090-86281
Nikhil Ghallayan (Section Leader)   ext 22006
Molecular Haematology Lab   ext 22005

For more inforamtion about the Molecular Haematology service at LabPLUS:

Molecular Haematology information page


Specimen Transport Instructions for Referring Laboratories


Information on Haemophilia A genetic testing:

Haemophilia A is caused by reduced levels of activity of the blood coagulation protein factor VIII. Except for a large inversion of the factor VIII gene in 10-20% of all haemophilia A patients, the mutations causing abnormal factor VIII are very heterogeneous.

Haemophilia A is an X-linked, recessive disorder. The segregation probabilities are thus 50% for each carrier female to transmit the defective gene to each child, male or female, while a haemophiliac father will only have normal sons and carrier daughters.

Carrier detection and prenatal diagnosis ideally would be performed by direct detection of the DNA defect in the factor VIII gene.  In the majority (80-90%) of haemophilia A families, the defect is due to missense and nonsense mutations and direct sequencing of the entire factor VIII coding region must be undertaken. 

In approximately 45% of all severe haemophilia A patients the gene defect is due to an inversion involving intron 22 of the FVIII gene. Analysis of this defect is performed by long range PCR. Other gross defects such as an inversion involving intron 1 (found in 1-4% of severe haemophilia A patients) and large deletions or insertions, once they have been identified, can be determined by conventional PCR. 


Last updated at 11:48:27 18/03/2021