Understanding What Are the 5 Types of Hemophilia?

October 1, 2025 •

3 min read

While the idea of five distinct types is a common misconception, there are four main forms of the bleeding disorder, which clarify what are the 5 types of hemophilia, when accounting for a milder, rarer version. Hemophilia is a disorder where the blood doesn't clot properly due to a deficiency in specific clotting factors. Understanding these distinctions is crucial for accurate diagnosis and management, as each type involves a deficiency in a different clotting protein.

Quick Summary

This article clarifies the four medically recognized types of hemophilia, explaining the differences between the common inherited types (A and B), the rarer inherited type C, and the acquired form. It details how deficiencies in specific clotting factors lead to varying severities of bleeding symptoms.

Key Points

Four Main Types: Contrary to the idea of five types, there are four primary forms: Hemophilia A, Hemophilia B, Hemophilia C, and Acquired Hemophilia.
Factor VIII and IX Deficiencies: Hemophilia A involves a deficiency in Factor VIII, and Hemophilia B is caused by a Factor IX deficiency; both are X-linked disorders most common in males.
Factor XI Deficiency: Hemophilia C, caused by a Factor XI deficiency, is an autosomal disorder that affects males and females equally and typically causes milder bleeding.
Autoimmune Form: Acquired hemophilia is not inherited but results from an autoimmune response that attacks clotting factors, usually appearing later in life.
Severity Depends on Factor Levels: The severity of hemophilia is determined by the amount of functional clotting factor present in the blood, which varies between types and individuals.
Treatment Varies by Type: Treatment involves replacing the missing factor through infusions, though the specific product and approach differ based on the type of hemophilia and its severity.

The clotting process is a complex cascade involving many proteins known as clotting factors. A deficiency or defect in any of these factors can disrupt the body's ability to form a proper blood clot, leading to prolonged and spontaneous bleeding episodes. The four main types of hemophilia are defined by the specific clotting factor that is missing or not functioning correctly. While the most common types are inherited, a rare form can be acquired later in life.

Hemophilia A (Classic Hemophilia)

Hemophilia A is the most prevalent form of the disorder, affecting about 1 in 5,000 male births. It is caused by a deficiency in or a defect of clotting Factor VIII (FVIII) and is an X-linked recessive disorder, primarily affecting males. The severity varies depending on FVIII levels, from mild cases with excessive bleeding after trauma to severe cases with spontaneous bleeding into muscles and joints.

Hemophilia B (Christmas Disease)

Hemophilia B, also known as Christmas Disease, results from a deficiency in or defect of clotting Factor IX (FIX). It is an X-linked recessive disorder and primarily affects males, similar to Hemophilia A. While symptoms are comparable to Hemophilia A, some studies suggest the bleeding tendency might be less severe at similar factor levels. It is less common than Hemophilia A.

Hemophilia C (Factor XI Deficiency)

Hemophilia C is a rare inherited bleeding disorder caused by a deficiency in or defect of clotting Factor XI (FXI). Unlike types A and B, it has an autosomal inheritance pattern, affecting males and females equally. Symptoms are typically milder, with spontaneous joint and muscle bleeding being uncommon, though excessive bleeding after surgery or trauma can occur. It is more prevalent among individuals of Ashkenazi Jewish descent.

Acquired Hemophilia

This is a non-genetic, autoimmune disorder that develops when the body produces antibodies that attack its own clotting factors, most often Factor VIII. It typically occurs in middle-aged or elderly individuals, or postpartum women. Symptoms can appear suddenly and mimic inherited forms. Diagnosis involves testing for factor levels and autoantibodies, with treatment focused on controlling bleeding and suppressing the immune system.

A Fifth Type? Addressing the Misconception

The idea of a 'fifth type' is often a misunderstanding related to other clotting factor deficiencies. Conditions like parahaemophilia (Factor V deficiency) and deficiencies in Factors I, II, VII, and X are recognized bleeding disorders but are not classified as subtypes of hemophilia. The primary hemophilia types remain A, B, and C based on their specific genetic causes and clinical presentations.

Comparison of Major Hemophilia Types


Feature	Hemophilia A	Hemophilia B	Hemophilia C	Acquired Hemophilia
Missing/Defective Factor	Factor VIII	Factor IX	Factor XI	Autoantibodies attack clotting factor (most often VIII)
Prevalence	Most common inherited type (~1 in 5,000 male births)	Second most common inherited type (~1 in 25,000 male births)	Rare (~1 in 100,000 people), more common in Ashkenazi Jews	Very rare (~1 in 1 million people)
Inheritance	X-linked recessive (primarily affects males)	X-linked recessive (primarily affects males)	Autosomal (affects males and females equally)	Not inherited (autoimmune disorder)
Joint/Muscle Bleeds	Common, especially in severe cases	Common, especially in severe cases (though potentially less severe than A)	Rare spontaneous bleeds	Possible, as symptoms mimic inherited forms
Treatment	Factor VIII replacement therapy, non-factor products (e.g., Hemlibra), gene therapy	Factor IX replacement therapy, gene therapy	Fresh frozen plasma (FFP), antifibrinolytics	Immunosuppressive therapy, bypassing agents

Diagnosis and Management

Diagnosis involves a medical history, physical exam, and blood tests, including clotting factor assays to identify the specific type and severity. Early diagnosis is important to prevent complications like joint damage from repeated internal bleeding. Management focuses on replacing the missing clotting factor, either as needed or preventatively (prophylaxis). Gene therapy and other medications are also used to manage bleeds and pain.

Conclusion

There are four main types of hemophilia: A, B, C, and the acquired form. These types are distinguished by the specific deficient clotting factor, which influences inheritance patterns, prevalence, and symptom severity. Advances in research and treatment continue to improve the outlook for individuals with hemophilia. The National Bleeding Disorders Foundation is a valuable resource for further information and support.

Frequently Asked Questions

Hemophilia A is caused by a deficiency of clotting Factor VIII, making it the most common type. Hemophilia B is caused by a deficiency of Factor IX and is less common. Both are inherited through the X chromosome and primarily affect males.

Yes, hemophilia A and B are X-linked recessive disorders, meaning males are more commonly and severely affected. Females are usually carriers, though they can have mild symptoms. Hemophilia C, however, is autosomal and affects males and females equally.

No. Acquired hemophilia is an autoimmune disorder that develops later in life when the body attacks its own clotting factors. Genetic hemophilia, such as types A, B, and C, is an inherited condition present from birth due to a faulty gene.

Diagnosis typically involves a medical history review and blood tests. Specialized factor assays measure the levels and function of specific clotting factors to identify the type and severity of the disorder.

Treatment usually involves factor replacement therapy to supply the missing clotting protein. This can be done on-demand or as a preventative measure (prophylaxis). For acquired hemophilia, immunosuppressants are also used. Novel therapies like gene therapy are also available for some patients.

With modern treatments, people with hemophilia can live full, healthy lives. The severity of the condition and access to comprehensive care, including preventative treatment, are key factors in managing symptoms and preventing long-term complications like joint damage.

Yes. While hemophilia is defined by specific factor deficiencies, other bleeding disorders exist. Von Willebrand disease, for instance, is the most common inherited bleeding disorder and involves a different clotting protein.