Hemophilia C is a rare bleeding disorder that affects males and females equally. It tends to be mild and may not require any treatment unless you’re having surgery or a dental procedure. Hemophilia C is also known as Rosenthal syndrome and factor XI (FXI) deficiency.

Read on to find out more about the symptoms of hemophilia C and how it’s inherited, diagnosed, and treated.

Who Gets Hemophilia C?

Hemophilia C is a rare type of hemophilia that affects about 1 in every 100,000 people in the United States. Hemophilia C is the fourth most common bleeding disorder and is rarer than hemophilia A and hemophilia B.

Hemophilia C can affect people of any age and from any race or ethnic group. It’s more common in people of Ashkenazi Jewish descent, thought to affect up to 8 percent of that population.

What Are the Symptoms of Hemophilia C?

The tendency to bleed is usually mild in people with hemophilia C, and the condition doesn’t typically cause spontaneous bleeding. However, people may experience uncontrollable or excessive bleeding after trauma, surgery, or dental procedures. After a surgical procedure, people with hemophilia C may have painful or swollen bruises known as hematomas. Babies with the condition undergoing circumcision may also have excessive bleeding. If left untreated, bleeding may continue for several hours and lead to anemia (low levels of red blood cells).

People with hemophilia C tend to bleed from mucosal membranes — the moist lining of the mouth, nose, and gut. Frequent or prolonged nosebleeds are a possible symptom of hemophilia C. Serious bleeding can also occur.

When Are Hemophilia C Symptoms an Emergency?

Symptoms of serious bleeding that need immediate medical attention include:

• Black, tarry stools (poop)
• Vomit that looks like coffee grounds
• Blood in your vomit
• Blood in your urine (pee)
• Bleeding after a tooth extraction that doesn’t stop for several hours

Hemophilia C Symptoms in Women

Though hemophilia C affects women and men equally, women with the condition experience specific symptoms, including:

• Menorrhagia (unusually long or heavy periods)
• Excessive or prolonged bleeding after childbirth
• Miscarriage of pregnancy

What Causes Hemophilia C?

Hemophilia C is caused by low levels of a blood clotting factor called factor XI, which stands for 11 in Roman numerals. FXI is a protein that plays a key role in forming blood clots that can stop bleeding. Factor XI helps to activate fibrin — a protein that traps platelets and holds the blood clot in place. With low levels of factor XI, your body has a harder time stopping bleeds.

How Is Hemophilia C Inherited?

The most common reason for a factor XI deficiency is inheriting a mutated version of the F11 gene — the gene that carries instructions on how to make factor XI. The F11 gene is usually inherited from your parents in an autosomal recessive pattern. This means that you must inherit the mutated F11 gene from both of your parents. Your parents can pass on a mutated version of the F11 gene even if they don’t have hemophilia C. In some cases, you can inherit hemophilia C from just one parent. The risk of inheriting hemophilia C is the same for males and females.

A genetic counselor can help you understand the risk of passing on the gene for hemophilia C.

In rare cases, hemophilia C isn’t inherited from parents. Rather, it’s caused by other conditions, such as systemic lupus erythematosus (SLE) (the most common form of lupus) or Noonan syndrome.

How Is Hemophilia C Diagnosed?

People with hemophilia C are usually diagnosed as adults after an episode of uncontrolled bleeding or during normal testing before a scheduled surgery. People with a family history of hemophilia C may be diagnosed before birth.

Your health care provider can diagnose hemophilia C based on your symptoms, family history, and test results.

Testing for Hemophilia C

Blood tests that can help confirm a hemophilia C diagnosis may include:

• Complete blood count
• Coagulation tests, including prothrombin time (PT) and activated partial thromboplastin time (aPTT)
• Factor XI assay

The results of coagulation tests may be abnormal in people with hemophilia C. Most people with hemophilia C have a normal PT but a prolonged aPTT. This means that it takes a longer time than normal for blood in the sample to clot.

A factor XI assay can measure the activity of factor XI in your blood. This test will show reduced activity in people with hemophilia C. It’s important to note that your factor XI activity may not match the severity of your symptoms.

How Severe Is Hemophilia C?

People with hemophilia C usually have mild symptoms that often don’t cause serious medical problems. Bleeding with hemophilia C usually doesn’t affect the joints or muscles as it can in people with hemophilia A or B.

The severity of hemophilia C doesn’t always match the levels of factor XI found in the blood. Someone with very low levels of factor XI may not have any symptoms. Additionally, people with normal factor XI levels may report symptoms related to bleeding.

How Is Hemophilia C Treated?

Treatment for hemophilia C is sometimes difficult because the bleeding tendency can be unpredictable. A referral to a hemophilia treatment center may be beneficial for people with hemophilia C.

You may not need treatment for hemophilia C unless you have surgery or get injured. If you do need treatment, there are a few options discussed below.

Fresh Frozen Plasma

Fresh frozen plasma (FFP) is a blood product made from donated blood that has coagulation factors, including factor XI. However, factor XI isn’t concentrated in FFP, so you may need to receive a large volume of FFP.

Another blood product called factor XI concentrate can overcome the need to give a large volume of FFP. However, this treatment option is only available in some European countries and carries a small risk of transmission of viral infections.

FFP is given intravenously (directly into a vein). Possible side effects of FFP include an allergic reaction and infection. The risk of infection is very low because all blood products are screened for the presence of viruses.

Antifibrinolytics

Antifibrinolytics are drugs that prevent clotting factors from breaking down. Examples of antifibrinolytics include aminocaproic acid (Amicar) and tranexamic acid (Cyklokapron). These drugs are often used to prevent bleeding during dental procedures or to stop nosebleeds. Antifibrinolytics can also help treat excessive menstrual bleeding.

These drugs come as pills that you take orally (by mouth) or a solution that’s administered intravenously. Antifibrinolytics are usually well tolerated, but side effects can occur. Possible side effects may include:

• Tiredness
• Blood clots
• Swelling
• Headache
• Muscle and joint pain

Hormonal Contraceptives

Hormonal contraceptives — also called birth control — can help to make periods more regular and reduce bleeding. Hormonal contraceptives come in several forms, including pills, injections, and intrauterine devices (IUDs).

One supportive measure that is especially helpful during dental procedures and circumcision is the use of fibrin glue. This is a freeze-dried concentrate of clotting factors that can be applied locally at the site of bleeding.

Can You Prevent Hemophilia C?

You can’t prevent hemophilia C because in most cases it’s a genetic condition that’s inherited from your parents. If you have hemophilia C and want to start a family, genetic counseling is available at many hemophilia treatment centers.

Talk With Others Who Understand

MyHemophiliaTeam is the social network for people with hemophilia and their loved ones. On MyHemophiliaTeam, more than 6,600 members come together to ask questions, give advice, and share their stories with others who understand life with hemophilia.

Are you living with hemophilia C? When was it diagnosed, and how has it affected your life? Share your experience in the comments below, or start a conversation by posting on your Activities page.