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Genetic and Rare Diseases Information Center (GARD)

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HHV-6 encephalitis

Other Names for this Disease
  • Human Herpesvirus 6 encephalitis
  • Variant A or HHV-6A
  • Variant B or HHV-6B
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HHV-6 encephalitis refers to inflammation of the brain due to an infection with human herpesvirus 6.  People who have undergone allogeneic hematopoietic cell transplantation are at an increased risk for developing HHV-6 encephalitis, particularly when umbilical cord blood stem cells are used.  People with immune system disorders may also be at an increased risk for developing this infection. Signs and symptoms vary, but often include confusion, anterograde amnesia (difficulty learning new information following the onset of amnesia), short-term memory loss, and seizures. Diagnosis often involves lumbar puncture, virus testing, and MRI. EEG's may also be recommended when seizures are suspected. HHV-6 encephalitis is treated with an antiviral agent with activity against HHV-6. Long term outlook (chance of full recovery) can vary considerably depending individual patient factors.[1]
Last updated: 9/30/2013


  1. Zerr D. Human herpesvirus 6 infection in hematopoietic cell transplant recipients. In: Basow DS. UpToDate. Waltham, MA: UpToDate; 2013;
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Basic Information

  • The HHV-6 Foundation provides information on HHV-6 and associated conditions on their Web site. Click HHV-6 Foundation to view the information.

In Depth Information

  • Medscape Reference provides information on this topic. Click on the link to view this information. 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 HHV-6 encephalitis. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles

  • Caserta MT, Mock DJ, Dewhurst S. Human herpesvirus 6. Clin Infect Dis. 2001 Sep 15;33(6):829-33. Epub 2001 Aug 10.