Clonal hematopoiesis (CH) happens when a cell called a hematopoietic stem cell, which can develop into different types of blood cells, starts making cells with the same genetic mutation. These blood cells have a different genetic pattern than the rest of your blood cells.

There are no warning signs of CH. Most people with CH never have any symptoms. Many people find out they have CH after genetic testing of their blood for other reasons.

CH can lead to blood cancers, especially myelodysplastic syndrome and acute myeloid leukemia. This is rare, however, and most people with CH never get blood cancer. Fewer than one out of every 100 people with CH get blood cancer each year.

People with CH also have a higher risk of cardiovascular problems, such as heart attacks. People with CH have about the same risk of having cardiovascular disease as people with diabetes.

1. What causes CH?

There is no single cause of CH, but some characteristics can increase your risk of developing CH, including:

• age
• being male
• being white
• smoking

Radiation therapy and some types of chemotherapy may be linked to CH, but more research is needed.

2. Should I be tested for CH?

Routine testing for CH isn’t recommended. This is because:

• There aren’t currently any treatments for CH.
• Most people with CH have a low risk of developing a blood cancer.
• Doctors are still learning about the relationship between cardiovascular disease and CH.

3. What should I do if I have CH?

As long as CH doesn’t progress to blood cancer, it requires no treatment.

If you have CH, visit a primary care doctor or cardiologist (heart specialist) to stay up to date with healthy heart recommendations. These include:

• keeping track of your blood pressure and controlling it if it’s high
• keeping track of your cholesterol and controlling it if it’s high
• following a healthy lifestyle
• quitting smoking, if you smoke

Some people may need other heart testing, such as a CT scan of their chest, to check for cardiovascular disease.

4. If I have CH, what are the risks to my children?

There aren’t any risks to your children. The genetic mutation that causes CH is not something you are born with. It develops during your lifetime, and only some of your blood cells have it. It can’t be passed down.

5. What is Memorial Sloan Kettering’s CH clinic?

MSK’s CH clinic is made up of CH specialists, including hematologists (blood specialists) and cardiologists. It is currently open to people who are already MSK patients.

Certain people with CH, such as those with a low blood count or a specific genetic pattern, are at a higher risk for blood cancers. They should be monitored through regular tests. Fewer than 5 percent of people with CH need to have this monitoring. If you do, your doctor will give you more information.

People with high-risk CH will have tests (such as blood tests or a bone marrow biopsy) to check for other blood disorders. All CH clinic patients also meet with a cardiologist to be screened for cardiovascular disease risk. This includes blood tests and sometimes additional heart testing.

If a diagnosis of a blood disorder is made, the CH clinic team will work with other blood cancer specialists at MSK to create a treatment plan.

If you would like more information about MSK’s CH clinic, talk with a member of your care team. To reach the CH clinic, please call 646-608-2393.