What is haemophilia?
Haemophilia is an inherited bleeding disorder where the blood doesn't clot properly. It is caused when blood does not have enough clotting factor. A clotting factor factor is a protein in blood that controls bleeding.
- Haemophilia A (also called classical haemophilia) is the most common form, and is caused by having low levels of factor VIII (8)
- Haemophilia B (sometimes called Christmas Disease) is caused by having low levels of factor IX (9).
In Australia there are more than 2,900 people diagnosed with haemophilia, who are mostly male. Severe haemophilia in females is very rare, but some females have lower factor levels and bleeding symptoms. Both males and females with less than 40% of the normal level of clotting factor are now recognised as having haemophilia.
Bleeding is most commonly internal. The low levels of clotting factor produce a wide range of bleeding episodes, usually into the joints or muscles. These bleeding episodes, or 'bleeds', may occur spontaneously, without an obvious cause, or as a result of trauma or injury. Specialised treatment is needed to help blood clot normally and is often infused or injected into a vein. If internal bleeding is not stopped quickly with treatment, it will result in pain and swelling. Over a period of time bleeding into joints and muscles can cause permanent damage such as arthritis, chronic pain and joint damage requiring surgery.
Date last reviewed: December 2020
How is haemophilia passed on?
Haemophilia is an inherited condition and occurs in families; however, in 1/3 of cases it appears in families with no previous history of the disorder. The genetic alteration causing haemophilia is passed down from parent to child through generations. Men with haemophilia will pass the altered gene on to their daughters but not their sons. Women who carry the altered gene can pass it on to their sons and daughters. Sons with the gene will have haemophilia. Most women and girls who carry the gene do not have bleeding symptoms. Others may have a bleeding tendency. If they have have low factor levels, women and girls will have haemophilia.
The diagrams below may assist in understanding this. The red males are those with haemophilia; the red and blue females carry the gene - they have X chromosome with the genetic alteration and one unaltered X chromosome.
Date last reviewed: September 2019
Where can I find more information?
For more information and frequently asked questions – click here - Haemophilia FAQ.
Download the HFA information booklets about haemophilia:
Haemophilia - [PDF, 1.7MB]
Living with mild haemophilia: a guide [PDF, 2.9MB]
Click here for other HFA publications on haemophilia.
Australian Bleeding Disorders Registry (ABDR) Annual Report 2017-2018. Canberra: National Blood Authority, 2019. [PDF, 1.12MB].
Australian Haemophilia Centre Directors' Organisation. Guidelines for the management of haemophilia in Australia. Canberra: National Blood Authority, 2016.
World Federation of Hemophilia. Guidelines for the management of hemophilia. 3rd edn. Montreal: WFH, 2020.
This resource was reviewed by Leonie Mudge and Kate Lenthen from Australia/New Zealand Haemophilia Social Workers’ and Counsellors’ Group; Anne Jackson, Penny McCarthy, Megan Walsh and Claire Bell from Australian Haemophilia Nurses’ Group; Ian d’Young, Abi Polus and Wendy Poulsen from Australian and New Zealand Physiotherapy Haemophilia Group; Katherine Rose, Senior Genetic Counsellor, Monash Medical Centre, Victoria; Dr Chris Barnes, Dr Simon Brown, Dr Simon McRae and Dr John Rowell from Australian Haemophilia Centre Directors’ Organisation; and bleeding disorder community representatives from HFA Haemophilia and Women’s Project Consumer Review Groups.
Date last reviewed: August 2020