Dentatorubral-pallidoluysian atrophy, commonly known as DRPLA, is a progressive brain disorder that causes involuntary movements, mental and emotional problems, and a decline in thinking ability. The average age of onset of DRPLA is 30 years, but this condition can appear anytime from infancy to mid-adulthood.
The signs and symptoms of DRPLA differ somewhat between affected children and adults. When DRPLA appears before age 20, it most often involves episodes of involuntary muscle jerking or twitching (myoclonus), seizures, behavioral changes, intellectual disability, and problems with balance and coordination (ataxia). When DRPLA begins after age 20, the most frequent signs and symptoms are ataxia, uncontrollable movements of the limbs (choreoathetosis), psychiatric symptoms such as delusions, and deterioration of intellectual function (dementia).
DRPLA is most common in the Japanese population, where it has an estimated incidence of 2 to 7 per million people. This condition has also been seen in families from North America and Europe.
Although DRPLA is rare in the United States, it has been studied in a large African American family from the Haw River area of North Carolina. When the family was first identified, researchers named the disorder Haw River syndrome. Later, researchers determined that Haw River syndrome and DRPLA are the same condition.
DRPLA is caused by a mutation in the ATN1 gene. This gene provides instructions for making a protein called atrophin 1. Although the function of atrophin 1 is unclear, it likely plays an important role in nerve cells (neurons) in many areas of the brain.
The ATN1 mutation that underlies DRPLA involves a DNA segment known as a CAG trinucleotide repeat. This segment is made up of a series of three DNA building blocks (cytosine, adenine, and guanine) that appear multiple times in a row. Normally, this segment is repeated 6 to 35 times within the ATN1 gene. In people with DRPLA, the CAG segment is repeated at least 48 times, and the repeat region may be two or three times its usual length. The abnormally long CAG trinucleotide repeat changes the structure of atrophin 1. This altered protein accumulates in neurons and interferes with normal cell functions. The dysfunction and eventual death of these neurons lead to uncontrolled movements, intellectual decline, and the other characteristic features of DRPLA.
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition.
As the altered ATN1 gene is passed from one generation to the next, the size of the CAG trinucleotide repeat often increases in size. Larger repeat expansions are usually associated with an earlier onset of the disorder and more severe signs and symptoms. This phenomenon is called anticipation. Anticipation tends to be more prominent when the ATN1 gene is inherited from a person's father (paternal inheritance) than when it is inherited from a person's mother (maternal inheritance).
Other Names for This Condition
- Haw River syndrome
- Myoclonic epilepsy with choreoathetosis
- Naito-Oyanagi disease
Additional Information & Resources
Genetic Testing Information
Genetic and Rare Diseases Information Center
Catalog of Genes and Diseases from OMIM
Scientific Articles on PubMed
- Adachi N, Arima K, Asada T, Kato M, Minami N, Goto Yi, Onuma T, Ikeuchi T, Tsuji S, Hayashi M, Fukutani Y. Dentatorubral-pallidoluysian atrophy (DRPLA) presenting with psychosis. J Neuropsychiatry Clin Neurosci. 2001 Spring;13(2):258-60. Citation on PubMed
- Hayashi Y, Kakita A, Yamada M, Koide R, Igarashi S, Takano H, Ikeuchi T, Wakabayashi K, Egawa S, Tsuji S, Takahashi H. Hereditary dentatorubral-pallidoluysian atrophy: detection of widespread ubiquitinated neuronal and glial intranuclear inclusions in the brain. Acta Neuropathol. 1998 Dec;96(6):547-52. Citation on PubMed
- Ikeuchi T, Koide R, Onodera O, Tanaka H, Oyake M, Takano H, Tsuji S. Dentatorubral-pallidoluysian atrophy (DRPLA). Molecular basis for wide clinical features of DRPLA. Clin Neurosci. 1995;3(1):23-7. Citation on PubMed
- Ikeuchi T, Onodera O, Oyake M, Koide R, Tanaka H, Tsuji S. Dentatorubral-pallidoluysian atrophy (DRPLA): close correlation of CAG repeat expansions with the wide spectrum of clinical presentations and prominent anticipation. Semin Cell Biol. 1995 Feb;6(1):37-44. Review. Citation on PubMed
- Katsuno M, Banno H, Suzuki K, Takeuchi Y, Kawashima M, Tanaka F, Adachi H, Sobue G. Molecular genetics and biomarkers of polyglutamine diseases. Curr Mol Med. 2008 May;8(3):221-34. Review. Citation on PubMed
- Koide R, Onodera O, Ikeuchi T, Kondo R, Tanaka H, Tokiguchi S, Tomoda A, Miike T, Isa F, Beppu H, Shimizu N, Watanabe Y, Horikawa Y, Shimohata T, Hirota K, Ishikawa A, Tsuji S. Atrophy of the cerebellum and brainstem in dentatorubral pallidoluysian atrophy. Influence of CAG repeat size on MRI findings. Neurology. 1997 Dec;49(6):1605-12. Citation on PubMed
- Licht DJ, Lynch DR. Juvenile dentatorubral-pallidoluysian atrophy: new clinical features. Pediatr Neurol. 2002 Jan;26(1):51-4. Citation on PubMed
- Tsuji S. Dentatorubral-pallidoluysian atrophy: clinical aspects and molecular genetics. Adv Neurol. 2002;89:231-9. Review. Citation on PubMed
- Veneziano L, Frontali M. DRPLA. 1999 Aug 6 [updated 2016 Jun 9]. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Mirzaa G, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2021. Available from http://www.ncbi.nlm.nih.gov/books/NBK1491/ Citation on PubMed
- Yamada M, Wood JD, Shimohata T, Hayashi S, Tsuji S, Ross CA, Takahashi H. Widespread occurrence of intranuclear atrophin-1 accumulation in the central nervous system neurons of patients with dentatorubral-pallidoluysian atrophy. Ann Neurol. 2001 Jan;49(1):14-23. Citation on PubMed