Down syndrome is a genetic disorder affecting 1 in every 700 infants. People with the condition have an increased risk of getting certain types of leukemia, a blood cancer.

An error during cell division, resulting in an extra (third) copy of chromosome 21, causes Down syndrome. Besides unique physical characteristics and developmental delays, people with Down syndrome are also at a higher risk of some health conditions.

Notably, they are more likely to develop certain types of leukemia. This is a cancer of the blood cells and is the most common cancer in children under the age of 15.

Read more to learn about the link between Down syndrome and leukemia, how it is diagnosed, and more.

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Leukemia occurs when there are too many immature white blood cells. In people with the disease, genetic changes cause issues with the mechanism controlling blood cell creation. This leads to an overproduction of white blood cells.

People with leukemia often have these genes on chromosome 21. Because people with Down syndrome have an extra copy of chromosome 21, they are more likely to have the faulty genes.

Children born with Down syndrome are 33 times more likely to develop acute lymphoblastic leukemia (ALL). They are also 150 times more likely to develop acute myeloid leukemia (AML). These are two of the most common types of leukemia.

Children with Down syndrome are also more likely to develop acute megakaryoblastic leukemia (AMKL), a rare type of AML.

According to the National Cancer Institute, the overall risk of developing leukemia for people with Down syndrome is 2.1% by 5 years old and 2.7% by 30 years old.

There is also a type of “preleukemia” known as transient leukemia (TL). This condition affects nearly 10% of newborn infants with Down syndrome.

Additionally, 1 in 5 infants with TL later develop AML. However, most infants do not develop symptoms, and the condition resolves without treatment.

Due to the increased risk of leukemia in children with Down syndrome, doctors usually recommend regular medical checkups.

However, in the United States, there is no set screening protocol for leukemia. Doctors can carry out a blood test in children who present some of the symptoms associated with leukemia or those who are at an increased risk.

Other countries have standardized guidelines for screening. For example, health authorities in the United Kingdom recommend that all infants born with Down syndrome receive a blood count and blood film in the first few days after birth.

In all cases, early detection of cancer leads to the best outcomes.

Some of the symptoms to look out for include:

  • having a fever or high temperature
  • being more tired than usual
  • getting recurrent infections
  • bruising easily with no obvious cause
  • developing petechiae (blood spots or rashes on the skin)

The leukemia treatment for people with Down syndrome is generally the same as the treatment for people without the condition. Usually, this means chemotherapy.

Chemotherapy works by lowering the number of blast cells (basic immature cells from which specialized cells develop) in the body.

Other available treatment types include:

  • stem cell transplant
  • radiotherapy
  • immunotherapy
  • biologics

It is important to note that people with Down syndrome may experience more severe side effects when undergoing chemotherapy than other people with cancer. If this happens, a doctor will adjust the treatment protocol to minimize side effects.

Children with Down syndrome have a higher cure rate for AML than the general population, especially those under the age of 5 when diagnosed.

The cure rate for all children with AML is around 75%. In children with Down syndrome who have AMKL, the cure rate is 80% to 100%. This is significantly higher than the 35% in children who do not have Down syndrome.

However, the cure rate for ALL in children with Down syndrome is 60–70%, slightly lower than the general population’s 75–85%. According to Leukemia Care, this may be because children with Down syndrome are more prone to infections and may react poorly to chemotherapy.

While recovery rates are generally high, doctors should closely monitor children with Down syndrome who have recovered from leukemia. This is because they have been shown to have a higher relapse rate than children who do not have the condition.

Living with cancer can be a huge emotional challenge for both an individual and their family.

The Leukemia & Lymphoma Society offers a range of support resources and information about organizations that can provide support to families. These include:

Find more resources and information in our dedicated cancer hub.

Children with Down syndrome are at an increased risk of developing leukemia due to an extra copy of chromosome 21. There is a higher cure rate for this group than for the general population for AML. However, the cure rate for ALL is slightly lower.

Infants with Down syndrome should receive regular checkups to monitor their status, as early detection is the best way to improve outcomes.