Congenital leukemia is a rare condition that develops in an unborn baby in the womb or during the first month of a baby’s life. It is more common in infants with inherited syndromes. The standard treatment is chemotherapy.

Congenital leukemia (CL) is a very rare condition that doctors diagnose at birth or within the first month of the baby’s life. The estimated 175–200 reported cases suggest that the condition affects about 1 in 5 million people.

This article explains what CL is and how doctors diagnose and treat it. It also looks at the risk factors for CL and the outlook for people with this condition.

Woman holding newborn baby.Share on Pinterest
Fly View Productions/Getty Images

CL is a leukemia diagnosis at birth or within 4 weeks of birth. Certain subtypes of leukemia are more common, with acute myeloid leukemia (AML) occurring more frequently than acute lymphoblastic leukemia (ALL) in newborns.

Both of these subtypes often involve genetic abnormalities, which occur in more than half of CL cases.

There are several types of CL:

  • AML
  • ALL
  • mixed phenotype acute leukemia (MPAL)
  • blastic plasmacytoid dendritic cell neoplasm

AML is more common than ALL, accounting for two-thirds of reported cases.

Learn more about AML in children.

Leukemia symptoms in infants are usually more severe than they are in older children. The possible symptoms of leukemia in infants include:

  • tiredness
  • weakness
  • feeling cold
  • paler skin than usual, which may not be apparent in people with dark skin tones
  • shortness of breath
  • frequent or persistent infections
  • fever
  • bruising or bleeding easily
  • severe or frequent nosebleeds
  • bleeding or swollen gums
  • swollen belly
  • lack of appetite
  • weight loss
  • swollen lymph nodes, which may appear as lumps under the skin in areas such as the underarms, groin, and neck
  • coughing or difficulty breathing
  • swollen face and arms
  • seizures and vomiting
  • rashes, including small, dark spots on the skin

Some of these symptoms can also be signs of other conditions or benign illnesses, but parents or caregivers should contact a doctor as soon as possible if they notice any of these symptoms or other unusual symptoms in a newborn.

As part of the diagnostic process for CL, doctors may carry out a range of tests, such as:

  • Complete blood count (CBC): A CBC is a blood test that shows the number of blood cells in the blood. Infants with leukemia may have an excess of white blood cells and not enough red blood cells.
  • Peripheral blood smear: A peripheral blood smear spreads a blood sample on a glass slide, which doctors will then examine under a microscope to check for abnormal blood cell changes.
  • Flow cytometry: Flow cytometry shows how a sample of cells from blood or bone marrow reacts to antibodies. It can help doctors identify leukemia subtypes.

Leukemia has no clear cause in infants, but it may occur due to:

  • changes in DNA within healthy bone marrow cells, resulting in bone marrow cells growing out of control and turning into leukemia cells
  • inherited DNA mutations from a parent
  • inherited conditions, such as Li-Fraumeni syndrome, which increases the risk of leukemia
  • exposure to radiation or chemicals that cause cancer
  • inherited genes that are less effective in eliminating harmful chemicals from the body, putting the person at higher risk of leukemia if they have exposure to harmful chemicals

According to earlier research from 2004, older maternal age is a risk factor for CL.

A 2016 case report notes that people with Down syndrome are 20 times as likely to have leukemia than those without this condition. About 2% of people with CL have Down syndrome.

According to the American Cancer Society, children with Down syndrome are at higher risk because they have an additional copy of chromosome 21.

The society also lists other risk factors for childhood leukemia:

  • Li-Fraumeni syndrome
  • ataxia-telangiectasia
  • Wiskott-Aldrich syndrome
  • Bloom syndrome
  • Shwachman-Diamond syndrome
  • having a sibling with leukemia
  • exposure to radiation

The treatment for infants with AML is usually the same as the treatment for older children. It might include chemotherapy alongside the drug gemtuzumab.

Infants with ALL require different treatment than older children with ALL. The treatment for infants with ALL may involve a range of chemotherapy drugs.

A 2019 analysis of 59 cases of CL reported that the overall 2-year survival rate was 44.2%. The median lifespan for infants with the disease was 210 days.

The researchers found no significant difference between the 2-year survival rates of infants who received chemotherapy and those who did not.

However, in infants with a KMT2A translocation, a genetic alteration common in AML, chemotherapy increased the average survival to 142 days compared with only 25 days with supportive therapy.

CL is a rare type of leukemia that doctors diagnose at birth or within a few weeks of birth. The most common type of CL is AML.

CL is often the result of inherited gene mutations or syndromes. Infants with Down syndrome have an increased risk of CL.

Doctors can carry out tests to diagnose CL, including a complete blood count and a peripheral blood smear.

The treatment may include chemotherapy drugs. The outlook for those with CL will often depend on the type of leukemia, the specific genetic mutations involved, and the response to treatment.