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Test ID: DRPL Dentatorubral-Pallidoluysian Atrophy (DRPLA) Gene Analysis, Varies

Reporting Name

DRPLA Gene Analysis

Useful For

Confirming the diagnosis of dentatorubral-pallidoluysian atrophy (DRPLA) for symptomatic patients


Predictive testing for individuals with a family history of DRPLA and a documented expansion in the ATN1 gene in an affected family member

Clinical Information

Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant neurodegenerative disorder characterized by ataxia, choreoathetosis, dementia, and psychiatric disturbance in adults and ataxia, myoclonus, seizures, and progressive intellectual deterioration in children. Characteristic neuropathologic observations include degeneration of the dentatorubral and pallidoluysian systems of the central nervous system.


The prevalence of DRPLA depends on the geographic and ethnic origin of the population being studied. DRPLA was first described in a European individual without a family history; however, it is predominantly found as an inherited condition and is most prevalent in Japan (0.2-0.7 per 100,000). Although rare, DRPLA has been identified in other populations, including Europe and North America.


DRPLA is caused by an expansion of the CAG trinucleotide repeat in the ATN1 (DRPLA) gene. This trinucleotide repeat is polymorphic in the general population, with the number of repeats ranging from 7 to 35. In affected individuals, the CAG expansion ranges from 48 to 93 repeats. As with other trinucleotide repeat disorders, anticipation is frequently observed, and larger CAG expansions are associated with earlier onset and a more severe and rapid clinical course. In DRPLA, the observed anticipation appears to be significantly greater in paternal transmissions.


An interpretive report will be provided.

Report Available

14 to 21 days

Day(s) Performed


Clinical Reference

1. 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

2. Tsuji S: Dentatorubral-pallidoluysian atrophy: clinical aspects and molecular genetics. Ad Neurol. 2002;89:231-239

3. Oyanagi S: Hereditary dentatorubral-pallidoluysian atrophy. Neuropathology. 2000 Sep;20 Suppl:S42-S46

Method Name

Polymerase Chain Reaction (PCR)

Specimen Type


Shipping Instructions

Specimen preferred to arrive within 96 hours of collection.

Specimen Required

Specimen Type: Whole blood

Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.


Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)

Reference Values

Normal alleles: 7-35 CAG repeats

Abnormal alleles: 49-93 CAG repeats


An interpretive report will be provided.

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

81177-ATN1 (ataxin 2) (eg, denatatorubral-pallidolyuysian atrophy) gene analysis, evaluation to detect abnormal (eg, expanded) alleles

LOINC Code Information

Test ID Test Order Name Order LOINC Value
DRPL DRPLA Gene Analysis In Process


Result ID Test Result Name Result LOINC Value
53234 Result Summary 50397-9
53235 Result 49631-5
53236 Interpretation 69047-9
53237 Specimen 31208-2
53238 Source 31208-2
53239 Released By 18771-6


1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing (Spanish) (T826)

2. Molecular Genetics: Neurology Patient Information

3. If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.

Mayo Clinic Laboratories | Neurology Catalog Additional Information: