Chronic lymphocytic leukemia (CLL) seems to have a genetic basis. However, the risk of passing it down remains low. If a person has a family member with CLL, they do not need to take any specific steps.

There is also no evidence that genetic testing is beneficial for CLL.

CLL is a form of blood cancer that begins in the bone marrow. It occurs when blood cells begin to grow abnormally. CLL is the most common type of leukemia in Western countries.

This article looks at whether CLL is hereditary. It also discusses whether a person with a family history of CLL should take any steps in relation to the condition.

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According to the National Library of Medicine, CLL has a genetic basis and appears to run in families.

Medical experts are unsure exactly how CLL passes from parent to child. However, researchers currently know that more than 40 genetic changes affect the inherited risk of CLL.

What is the risk of inheriting CLL?

There is some uncertainty about the exact hereditary risk of CLL.

The American Cancer Society (ACS) suggests that people who have first-degree relatives with CLL are more than twice as likely to develop the condition as those whose relatives have not had it.

The Leukemia and Lymphoma Society (LLS) states that people with first-degree relatives with CLL are 5–8 times more likely to develop it.

However, even if a person has a first-degree relative with CLL, the overall risk of developing CLL appears to be low. This is because the average lifetime risk of developing CLL is low.

Additionally, the ACS stresses that inherited DNA mutations rarely cause CLL. Instead, a person is more likely to develop CLL due to DNA changes that they acquire over their lifetime.

A person with a family history of CLL does not need to take any specific measures. As the LLS makes clear, even people with a family history of CLL have only a small risk of developing it.

Many people do not experience symptoms of CLL. However, anyone who has a family history of CLL may wish to be more mindful of possible CLL symptoms such as:

  • fatigue
  • weakness
  • unintended weight loss
  • chills
  • fever
  • swollen lymph nodes
  • night sweating
  • abdominal pain
  • a feeling of fullness even after a small meal

For genetic testing, medical professionals take samples of bodily tissues or fluids to find evidence of specific genetic mutations.

There is no evidence that genetic testing for CLL is beneficial for people who have no signs of the condition. However, genetic testing can be useful during the diagnostic process.

According to the ACS, doctors sometimes recommend genetic testing on bone marrow cells. This is because, in some cases of CLL, certain chromosomal changes can occur. These include:

  • missing 13, 11, and 17 chromosomes
  • an extra copy of chromosome 12
  • a swapping of the DNA between chromosomes 12 and 14

Genetic testing can also help determine the outlook for people with CLL. For instance, a missing chromosome 13 can mean a better outlook.

CLL may be hereditary, but researchers are unsure about the extent of this risk.

Research has shown that having a first-degree relative with CLL may increase a person’s risk of developing this condition. But the overall chance of developing CLL remains low, even for those with a family history.

Researchers are continuing to investigate the genetic basis of CLL. It is still unclear which genetic changes may be responsible for increasing the risk. However, researchers have identified genetic changes that seem to affect the outlook for people with CLL.