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Disease Profile

Human T-cell leukemia virus type 2

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)

HTLV-2; Human T lymphotropic virus type 2


Viral infections


Human Tcell leukemia virus, type 2 (HTLV-2) is a retroviral infection that affect the T cells (a type of white blood cell). Although this virus generally causes no signs or symptoms, scientists suspect that some affected people may later develop neurological problems and/or chronic lung infections. HTLV-2 is spread by blood transfusions, sexual contact and sharing needles. It can also be spread from mother to child during birth or breast-feeding.[1][2] There is no cure or treatment for HTLV-2 and it is considered a lifelong condition; however, most infected people remain asymptomatic (show no symptoms) throughout life.[2]


Human Tcell leukemia virus, type 2 (HTLV-2) generally causes no signs or symptoms. Although HTLV-2 has not been definitively linked with any specific health problems, scientists suspect that some affected people may later develop neurological problems such as:[1][2]

Although evidence is limited, there may also be a link between HTLV-2 and chronic lung infections (i.e. pneumonia and bronchitis), arthritis, asthma, and dermatitis.[2]


Human Tcell leukemia virus, type 2 (HTLV-2) occurs when a person is infected by the human T-cell leukemia retrovirus. HTLV-2 is spread by blood transfusions, sexual contact and sharing needles. It can also be spread from mother to child during birth or breast-feeding. It is unclear why some people with HTLV-2 may develop neurological problems and other medical conditions, while others remain asymptomatic (show no signs or symptoms) their entire lives.[1][2]


Human Tcell leukemia virus, type 2 (HTLV-2) is usually diagnosed based on blood tests that detect antibodies to the virus. However, HTLV-2 is often never suspected or diagnosed since most people never develop any signs or symptoms of the infection. Diagnosis may occur during screening for blood donation, testing performed due to a family history of the infection, or a work-up for an HTLV-2-associated medical problems.[1][2]


No cure or treatment exists for human Tcell leukemia virus, type 2 (HTLV-2). Management is focused on early detection and preventing the spread of HTLV-2 to others. Screening blood doners, promoting safe sex and discouraging needle sharing can decrease the number of new infections. Mother-to-child transmission can be reduced by screening pregnant women so infected mothers can avoid breastfeeding.[2][1]

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 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.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Human T-cell leukemia virus type 2. Click on the link to view a sample search on this topic.


  1. HTLV Type I and Type II. NORD. May 2012; https://www.rarediseases.org/rare-disease-information/rare-diseases/byID/1203/viewAbstract.
  2. Ewa Maria Szczypinska, MD. Human T-Cell Lymphotropic Viruses. Medscape. August 2014; https://emedicine.medscape.com/article/219285-overview.

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