Tests included: SCA1, SCA2, SCA3, SCA6, and SCA7
Gene Symbols: ATXN 1, 2, 3, 6 & 7
Chromosomal Locus: See individual tests for details
Pseudonyms: Ataxia, Neuromuscular
TURNAROUND TIME: 15 days
Different polymerase chain reactions (PCR) that brackets the trinucleotide repeat regions. See individual test pages for more details.
- Collect:Prefer two 5ml whole blood EDTA (lavender top) tube.
- Min. Collection: 0.7 ml whole blood EDTA.
- Transport: blood EDTA at Room Temp shipped regular next day air (No Saturday delivery; store specimen refrigerated and ship Monday).
- Stability: Ambient: up to 7 days; Refrigerated: 2 weeks. Frozen: unacceptable
- Unacceptable Conditions: Serum. Frozen or severely hemolyzed blood. Clotted blood.
Prenatal testing:Direct: 5ml direct unspun amniotic fluid or 3mm3 CVS tissue with a backup flask growing. Culture: confluent T25 flask. Maternal blood sample is required for maternal cell contamination studies.
Counseling and informed consent are recommended for genetic testing. A consent form
is available as a resource.
Inheritance:Mostly autosomal dominant. Variable age of onset but complete penetrance.
See details in individual test pages
Molecular Genetic Mechanism: See details on individual sheets
Clinical Sensitivity: 99%. Over 95% of ataxia conditions (by incidence) are encompassed by this panel.
Analytical Sensitivity: 99%
Test Limitations: This testing examines the trinucleotide repeat regions, exclusively. However, no other mechanism has been described for these conditions and the testing is considered diagnostic. Rare diagnostic errors can occur due to primer or probe site mutations or rare polymorphisms.
INDICATIONS FOR USE:
- Individuals with a family history of ataxias who want to determine their true risk.
- Families considering future medical and disability insurance needs.
- Individuals at risk who wish prenatal diagnosis.
- To determine whether individuals with an ataxia have one of these conditions
- To differentiate individuals with the ataxias.
OMIM – see specific tests