Submitted Successfully!
Thank you for your contribution! You can also upload a video entry or images related to this topic.
Version Summary Created by Modification Content Size Created at Operation
1 + 562 word(s) 562 2020-12-15 07:15:23

Video Upload Options

Do you have a full video?


Are you sure to Delete?
If you have any further questions, please contact Encyclopedia Editorial Office.
Yang, C. Alpers-Huttenlocher Syndrome. Encyclopedia. Available online: (accessed on 27 February 2024).
Yang C. Alpers-Huttenlocher Syndrome. Encyclopedia. Available at: Accessed February 27, 2024.
Yang, Catherine. "Alpers-Huttenlocher Syndrome" Encyclopedia, (accessed February 27, 2024).
Yang, C. (2020, December 24). Alpers-Huttenlocher Syndrome. In Encyclopedia.
Yang, Catherine. "Alpers-Huttenlocher Syndrome." Encyclopedia. Web. 24 December, 2020.
Alpers-Huttenlocher Syndrome

Alpers-Huttenlocher syndrome is one of the most severe of a group of conditions called the POLG-related disorders. The conditions in this group feature a range of similar signs and symptoms involving muscle-, nerve-, and brain-related functions. Alpers-Huttenlocher syndrome typically becomes apparent in children between ages 2 and 4. People with this condition usually have three characteristic features: recurrent seizures that do not improve with treatment (intractable epilepsy), loss of mental and movement abilities (psychomotor regression), and liver disease.

genetic conditions

1. Introduction

People with Alpers-Huttenlocher syndrome usually have additional signs and symptoms. Most have problems with coordination and balance (ataxia) and disturbances in nerve function (neuropathy). Neuropathy can lead to abnormal or absent reflexes (areflexia). In addition, affected individuals may develop weak muscle tone (hypotonia) that worsens until they lose the ability to control their muscles and movement. Some people with Alpers-Huttenlocher syndrome lose the ability to walk, sit, or feed themselves. Other movement-related symptoms in affected individuals can include involuntary muscle twitches (myoclonus), uncontrollable movements of the limbs (choreoathetosis), or a pattern of movement abnormalities known as parkinsonism.

Affected individuals may have other brain-related signs and symptoms. Migraine headaches, often with visual sensations or auras, are common. Additionally, people with this condition may have decreased brain function that is demonstrated as sleepiness, inability to concentrate, irritability, or loss of language skills or memory. Some people with the condition may lose their eyesight or hearing. People with Alpers-Huttenlocher syndrome can survive from a few months to more than 10 years after the condition first appears.

2. Frequency

The prevalence of Alpers-Huttenlocher syndrome is approximately 1 in 100,000 individuals.

3. Causes

Alpers-Huttenlocher syndrome is caused by mutations in the POLG gene. This gene provides instructions for making one part, the alpha subunit, of a protein called polymerase gamma (pol γ). Pol γ functions in mitochondria, which are structures within cells that use oxygen to convert the energy from food into a form cells can use. Mitochondria each contain a small amount of DNA, known as mitochondrial DNA (mtDNA), which is essential for the normal function of these structures. Pol γ "reads" sequences of mtDNA and uses them as templates to produce new copies of mtDNA in a process called DNA replication.

Most POLG gene mutations change single protein building blocks (amino acids) in the alpha subunit of pol γ. These changes result in a mutated pol γ that has a reduced ability to replicate DNA. Although the mechanism is unknown, mutations in the POLG gene often result in a reduced number of copies of mtDNA (mtDNA depletion), particularly in muscle, brain, and liver cells. MtDNA depletion causes a decrease in cellular energy, which could account for the signs and symptoms of Alpers-Huttenlocher syndrome.

A mutation in the POLG gene has not been identified in approximately 13 percent of people diagnosed with Alpers-Huttenlocher syndrome. Researchers are working to identify other genes that may be responsible for the condition.

4. Inheritance

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

5. Other Names for This Condition

  • Alpers diffuse degeneration of cerebral gray matter with hepatic cirrhosis

  • Alpers disease

  • Alpers progressive infantile poliodystrophy

  • Alpers syndrome

  • diffuse cerebral sclerosis of Schilder

  • progressive sclerosing poliodystrophy


  1. Chan SS, Longley MJ, Copeland WC. The common A467T mutation in the humanmitochondrial DNA polymerase (POLG) compromises catalytic efficiency andinteraction with the accessory subunit. J Biol Chem. 2005 Sep 9;280(36):31341-6.
  2. Cohen BH, Chinnery PF, Copeland WC. POLG-Related Disorders. 2010 Mar 16[updated 2018 Mar 1]. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH,Stephens K, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): Universityof Washington, Seattle; 1993-2020. Available from
  3. Milone M, Massie R. Polymerase gamma 1 mutations: clinical correlations.Neurologist. 2010 Mar;16(2):84-91. doi: 10.1097/NRL.0b013e3181c78a89. Review.
  4. Moraes CT, Shanske S, Tritschler HJ, Aprille JR, Andreetta F, Bonilla E, SchonEA, DiMauro S. mtDNA depletion with variable tissue expression: a novel geneticabnormality in mitochondrial diseases. Am J Hum Genet. 1991 Mar;48(3):492-501.
  5. Nguyen KV, Sharief FS, Chan SS, Copeland WC, Naviaux RK. Molecular diagnosisof Alpers syndrome. J Hepatol. 2006 Jul;45(1):108-16.
  6. Rocher C, Taanman JW, Pierron D, Faustin B, Benard G, Rossignol R, Malgat M,Pedespan L, Letellier T. Influence of mitochondrial DNA level on cellular energy metabolism: implications for mitochondrial diseases. J Bioenerg Biomembr. 2008Apr;40(2):59-67. doi: 10.1007/s10863-008-9130-5.
  7. Stumpf JD, Copeland WC. Mitochondrial DNA replication and disease: insightsfrom DNA polymerase γ mutations. Cell Mol Life Sci. 2011 Jan;68(2):219-33. doi:10.1007/s00018-010-0530-4.
Contributor MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to :
View Times: 468
Entry Collection: MedlinePlus
Revision: 1 time (View History)
Update Date: 24 Dec 2020