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Disease Profile

Chronic lymphocytic leukemia

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Leukemia, lymphocytic, chronic; Chronic B-Cell Lymphocytic Leukemia; B Cell Chronic Lymphocytic Leukemia


Rare Cancers


Chronic lymphocytic leukemia (CLL) is a type of cancer of the white blood cells (lymphocytes). Early signs and symptoms may include swollen lymph nodesfatigue, weight loss, fever, night sweats and/or frequent infections. CLL usually occurs in adults around the age of 70 and begins in the bone marrow and then spreads to the blood. Over time, CLL may also spread to the lymph nodes and other organs, including the liver, spleen and lungs. The severity and outcome of CLL depends on many factors. The underlying cause is thought to be a combination of genetic and other unknown factors. It usually occurs in people with no family history of the condition, but familial cases have been reported. CLL is diagnosed based on the symptoms and various blood tests. Treatment options depend on many factors, including the stage of the condition, blood cell counts, and whether the CLL has recurred (come back).[1][2][3][4]


The following list includes the most common signs and symptoms in people with chronic lymphocytic leukemia (CLL). These features may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list does not include every symptom or feature that has been described in this condition.

Signs and symptoms may include:[1][4]

  • Enlarged lymph nodes
  • Enlarged liver and/or spleen
  • Night sweats
  • Fever
  • Fatigue
  • Loss of appetite
  • Weight loss
  • Frequent infections
  • Abnormal bruising

Some people with CLL have no symptoms at the time of diagnosis, and CLL is found by chance during a routine blood test. Symptoms usually develop slowly, although CLL can progress quickly in rare cases. Bone marrow changes may lead to low blood oxygen (anemia) and a low platelet count (thrombocytopenia). The severity of CLL may depend on genetic and other factors, including the presence of underlying health conditions.[3] 

It is thought that CLL occurs following a pre-cancerous condition known as monoclonal B-cell lymphocytosis (MBL). MBL is present in about 10 percent of healthy adults. Only a small percentage of people with MBL develop CLL.[3]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Autosomal dominant somatic cell mutation
Cellular immunodeficiency
Chronic lymphatic leukemia
Somatic mutation


The underlying cause of chronic lymphocytic leukemia (CLL) is not known. About 10% of people with CLL have a family history of this condition.[1] Other risk factors include age, exposure to pesticides or herbicides, allergic conditions, and a current hepatitis C infections.[1]


Chronic lymphocytic leukemia (CLL) is diagnosed through a clinical examination and specific blood tests. Sometimes CLL is first detected by chance during a routine blood test. Tests that may be used to confirm a diagnosis of CLL include a blood count, peripheral blood smear, flow cytometry, and a biopsy of the bone marrow or lymph nodes.[1][2] 


Treatment for chronic lymphocytic leukemia (CLL) depends on many factors. These include the symptoms, the stage of the CLL, other diseases that are present, and whether the CLL has come back. People with early stage CLL who have no symptoms may simply be closely monitored by their doctor without any treatment. Treatment options may include, chemotherapy, radiation therapy, and targeted therapy (drugs used to find and kill cancer cells without hurting normal cells). In younger patients, bone marrow or stem cell transplantation may be an option. More information about the treatment of CLL can be viewed on the National Cancer Institute's page about CLL treatment.[2][3][4]

Specialists involved in the care of someone with CLL may include:

  • Medical oncologist
  • Radiation oncologist
  • Hematologist 
  • Surgeon

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Organizations Providing General Support

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

      • The American Cancer Society provides information on Chronic lymphocytic leukemia. Please click on the link to access this resource.
      • The Leukemia and Lymphoma Society has an information page on Chronic lymphocytic leukemia. Click on the link to view this information page.
      • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
      • The Merck Manual provides information on this condition for patients and caregivers.
      • The National Cancer Institute provides the most current information on cancer for patients, health professionals, and the general public.
      • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

        In-Depth Information

        • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
        • The Merck Manual for health care professionals provides information on Chronic lymphocytic leukemia.
        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Chronic lymphocytic leukemia. Click on the link to view a sample search on this topic.


          1. Hallek M, Shanafelt TD, Eichhorst B. Chronic lymphocytic leukaemia. Lancet. 2018; 391(10129):1524-1537. https://pubmed.ncbi.nlm.nih.gov/29477250.
          2. Hallek M. Chronic lymphocytic leukemia: 2020 update on diagnosis, risk stratification and treatment. Am J Hematol. 2019; 94(11):1266-1287. https://pubmed.ncbi.nlm.nih.gov/31364186.
          3. Bosch F, Dalla-Favera R. Chronic lymphocytic leukaemia: from genetics to treatment. Nat Rev Clin Oncol. 2019; 16(11):684-701. https://pubmed.ncbi.nlm.nih.gov/31278397.
          4. Milne K, Sturrock B, Chevassut T. Chronic Lymphocytic Leukaemia in 2020: the Future Has Arrived. Curr Oncol Rep. 2020; 22(4):36. https://pubmed.ncbi.nlm.nih.gov/32172299.

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