Myeloproliferative neoplasms (MPNs) are types of blood cancer that cause stem cells in the bone marrow to make too many platelets, red blood cells, or white blood cells. After a person is diagnosed with one of these conditions, they may wonder whether their family members are also at risk.

MPNs are most often linked to environmental or lifestyle factors or have no clear cause. In some cases, genetic factors that increase risk are passed down through families. However, this is rare. Most people who have a family member with an MPN won’t develop the condition themselves.

MPNs and Gene Changes

Genes provide instructions that tell each cell what to do. They help determine how long a cell lives, tell the cell when to divide and produce new cells, and control what jobs the cell performs in the body. You get genes from both of your parents, and if you have children, you will pass some of your genes along to them.

Like other types of cancer, MPNs are caused by gene changes (mutations) that allow cells to divide and grow in a disorganized way. Anything that increases a person’s risk of developing genetic mutations within blood cells can also increase the risk of MPNs.

Acquired vs. Inherited Genes

There are two main types of genetic mutations. Inherited mutations, also called germline mutations, are passed down from parent to child. They are present at birth within every cell in the body. Rarely, inherited gene mutations can lead to multiple cases of cancer within the same family.

Acquired mutations, on the other hand, develop during a person’s lifetime. They may occur in just one cell or a few. These changes, also known as somatic mutations, can be caused by environmental or lifestyle factors (such as smoking) that damage a cell’s DNA. This type of gene mutation isn’t generally passed down from parent to child.

Are MPNs Caused by Inherited Gene Changes?

Most cases of MPNs are thought to be caused by acquired mutations that won’t affect other people in your family. The majority of people with this condition don’t have a family history of the disease.

Many people with the three types of “classic” MPNs — primary myelofibrosis (PMF), essential thrombocythemia (ET), and polycythemia vera (PV) — have changes in the JAK2 gene, leading to a mutation called JAK2 V617F. Other mutations in the MPL or CALR genes can also cause the classic MPNs. All of these mutations trigger the production of too many blood cells. They are acquired gene mutations that develop later in life.

Other types of MPNs develop in similar ways. Chronic myeloid leukemia is an MPN that is almost always caused by a gene change called the Philadelphia chromosome. This abnormality happens when parts of two different chromosomes (the long pieces of DNA that contain genes) break off and swap places. This is also an acquired gene mutation that isn’t passed down to children. More rare forms of MPNs are also generally thought to develop due to acquired gene changes.

Doctors have discovered a few cases in which MPNs can run in families. They may refer to these cases as “familial MPNs.” Additionally, other inherited gene changes can make MPNs more likely to occur. Certain MPN risk factors may also be hereditary, increasing each family member’s chance of being diagnosed with this condition.

Familial MPNs

Familial MPNs often lead to multiple cases of PMF, ET, or PV within the same family. They occur when a specific inherited mutation is passed down from parent to child. About 7.6 percent of MPNs are familial MPNs.

Researchers have identified two general types of familial MPNs. In one type, an MPN develops soon after birth or during the early part of a person’s childhood. Several different types of gene mutations can cause this type of familial MPN, including changes in the MPL gene. Most people who inherit these types of gene mutations will develop MPNs.

In another type of familial MPN, the condition occurs later in life. People with this disorder have inherited mutations that increase the likelihood of developing the same acquired mutations seen in most other cases of MPNs (mutations in the JAK2, MPL, and CALR genes). Experts aren’t always sure which gene mutations cause familial MPNs, but researchers are continuing to study this area.

Other MPN subtypes may also be rarely connected to an inherited mutation. For example, researchers have identified cases of chronic neutrophilic leukemia that appear to be caused by a mutation passed down within a family.

If you have a familial MPN, you may pass on gene mutations to your children that also increase their MPN risk. Talk to your doctor to learn more about whether your condition was likely to be caused by inherited or acquired gene changes.

Other Inherited Gene Mutations

Recent studies have found that some genes passed down within families can lead to an MPN predisposition without causing a familial MPN. One study found that when one person was diagnosed with an MPN, their family members were five to seven times more likely to also develop the condition. However, it is important to note that these disorders are fairly rare, and your risk of getting them is still low even if you have a family history of MPNs.

Researchers are starting to uncover some of the gene changes that may make MPNs more likely to develop. In particular, they have found that there are different versions or “variants” of the JAK2 gene. People with a certain variant of JAK2 are more likely to develop the JAK2 V617F mutation that causes MPNs. This JAK2 variant can be passed down in families — multiple people in the family have an increased risk of having MPN-causing gene mutations.

Hereditary MPN Risk Factors

Some factors that can increase the risk of MPNs are genetic, and others are related to the environment.

Race and ethnicity can play a role. People of Jewish descent whose families are originally from Eastern Europe have a higher risk of developing PV, while white people have an elevated chance of developing PMF.

Some risk factors may have both genetic and lifestyle components. For example, obesity can make a person more likely to be diagnosed with essential thrombocythemia. Although obesity is linked to lifestyle factors like diet and physical activity levels, it also has a genetic component. Genes control things like metabolism and hormone balances that have an impact on weight.

Likewise, smoking cigarettes can lead to MPNs. You can pick up habits like smoking from your parents, but researchers have also discovered certain gene changes that can make you more likely to become addicted to cigarettes.

Some MPN risk factors can affect multiple family members but are environmental rather than genetic factors. For example, exposure to chemicals can sometimes lead to MPNs. This most often happens due to a workplace environment, but it may also happen because of environmental pollution. Per an article in MPN Voice, researchers are studying whether coal waste in the environment may have caused an increased number of PV cases in a Pennsylvania town. This finding could lead to multiple cases of MPNs in a family as well as in a neighborhood. Research is still being conducted in this area.

Can MPNs Be Prevented?

You can’t completely prevent MPNs from developing. Additionally, there’s no way to change the genes you were born with, so there isn’t any way to prevent having inherited mutations or other genetic risk factors.

MPNs don’t normally run in families. However, if someone in your family had an MPN, you can ask your doctor whether there is a chance your condition was caused by inherited gene changes and whether you may pass these mutations on to your children.

Talk With Others Who Understand

Find others to connect with at myMPNteam, the social network for people living with myeloproliferative neoplasms and their loved ones. On myMPNteam, more than 2,500 members come together to ask questions, give advice, and share their stories with others who understand life with MPNs.

Do you have family members diagnosed with an MPN? Share your experience in the comments below, or start a conversation by posting on your Activities page.