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Types of blood disorders

Discover more about the science behind different types of blood disorders, from hemophilia to rare clotting factor deficiencies and women living with hemophilia.


Hemophilia is a rare genetic blood disorder, in which the blood does not clot as it should. It can also lead to spontaneous internal and external bleeding. People with hemophilia are missing or do not have enough clotting factor, a protein in the blood that helps to control bleeding and clotting.

Hemophilia is divided into two different types, A and B, both of which predominantly affect men. The most common type of hemophilia is 'hemophilia A', and affects around one in every 10,000 males. Hemophilia A is caused by people not having enough clotting factor VIII (factor eight). Hemophilia B is less common than hemophilia A, affecting around one in 50,000 males. A person with hemophilia B does not have enough factor IX (factor nine).


Depending on how much of the clotting factor a person has, will determine whether their condition is classed as mild, moderate or severe. For example:

  • Severe hemophilia means that factor levels < 1%
  • Moderate hemophilia means that factor levels are 1–5%
  • Mild hemophilia means that factor levels are 6 – < 40%

For people with severe hemophilia, these incredibly low levels of factor (<1%) mean that they will bleed following injury, but what can be most difficult is that people will have frequent spontaneous bleeding episodes, often inside their body.


Srivastava A, Santagostino E, Dougall A, Kitchen S, Sutherland M, Pipe SW, Carcao M, Mahlangu J, Ragni MV, Windyga J, Llinás A,

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Hemophilia panelists and co-authors. WFH Guidelines for the Management of Hemophilia, 3rd edition. Haemophilia. 2020 Aug;26 Suppl

6:1-158. doi: 10.1111/hae.14046. Epub 2020 Aug 3. Erratum in: Haemophilia. 2021 Jul;27(4):699. PMID: 32744769.


Due to the genetics of hemophilia, it occurs mostly in men; however, women can be carriers and also experience symptoms. 

We all have two chromosomes which we inherit from our parents. Females inherit two X chromosomes, one from their mother and one from their father (XX). Males inherit an X chromosome from their mother and a Y chromosome from their father (XY). The gene for hemophilia is located only on the X chromosome. So, if a son inherits an X chromosome carrying hemophilia from his mother, he will have hemophilia. A father with hemophilia cannot pass it on to his sons, but will pass the gene to his daughters. Because females have two X chromosomes, even if they inherit a hemophilia gene, they have another healthy X chromosome to take over, instead they will be a carrier. Carriers have around half the normal amount of factor VIII and factor IX and can also suffer symptoms



Hemophilia is well documented in males; however, it is often not recognised in women, who may also be living with symptoms. Recent research has suggested that some carriers have increased and longer bleeding during menstruation compared with non-carriers. These female carriers may suffer a number of symptoms including:

  • Bruising more easily
  • Prolonged bleeding after surgery
  • Serious bleeding after trauma and longer time to heal
  • More likely to require an iron supplement or to undergo hysterectomy and are more likely to have bleeding following childbirth.

Along with the physical symptoms, there may be a psychological and mental health impact from being a hemophilia carrier - discover how Olivia lives with being not only a carer for her son Harry, but also being a hemophilia carrier.

Acquired hemophilia

Acquired hemophilia is a rare condition that affects both men and women in adult life. It is caused by an auto-antibody, produced by the immune system, which inactivates factor VIII proteins (factor VIII is a clotting factor protein in the blood that helps to control bleeding and clotting).

Acquired hemophilia can lead to significant bleeding; however, the bleeding pattern seen is very different from the more common congenital hemophilia. Bleeding into the joints is much less common, the person will bleed into the skin and soft tissues. Discover how Linda was diagnosed and what it is like to be living with acquired hemophilia.

Rare clotting factor deficiencies

Clotting factor deficiencies are rare disorders in which one of several clotting factors is missing or not working properly. These rare diseases a still being learned about within the scientific community as they are diagnosed so rarely. Find out more about living with rare clotting factor deficiencies.


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The Hemophilia Society. Bleeding Disorders Hemophilia A. 2020 [Available from https://hemophilia.org.uk/bleeding-disorders/hemophilia-a/ Last Accessed January 2021]

The Hemophilia Society. Bleeding Disorders. Hemophilia B. 2020 [Available from https://hemophilia.org.uk/bleeding-disorders/hemophilia-b/ Last Accessed January 2021]

National Hemophilia Foundation. Bleeding Disorders. Hemophilia A. 2020 [Available from https://www.hemophilia.org/bleeding-disorders-a-z/types/hemophilia-a Last Accessed January 2021]

Hirayama AB, et al. Hematol Transfus Cell Ther. 2019;41:349-355

MedlinePlus 2020 National Institutes of Health. Hemophilia. Available from https://medlineplus.gov/genetics/condition/hemophilia/. Last Accessed January 2021

Paroskie A, et al. Br J Haematol. 2015;170:223-228

World Federation of Hemophilia, eLearning Centres, Carrier and Women with Hemophilia, 2020. Available from https://elearning.wfh.org/elearning-centres/carriers-and-women-with-hemophilia/#carriers_bleeding_symptoms Last Accessed January 2021.

Giangrande P. Acquired Hemophilia. World Federation of Hemophilia. No 38. Nov 2012 


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