Spinocerebellar Ataxia 7

General Information

Lab Name

Lab Code

SCA7T

Epic Ordering

Spinocerebellar Ataxia 7

Description

For further information about this test, see Spinocerebellar Ataxia Panel [SCAPN], which includes panels 1,2,3,6 and 7.

Synonyms

OPCA with Retinal Degeneration, OPCA3, SCA7

Components

Code	Name
SCA7A1	ATXN7 (SCA7), allele 1
SCA7A2	ATXN7 (SCA7), allele 2
SCAITP	SCA1 Interpretation
SCACOM	SCA1 Comment
SCA7DI	SCA7 Director

Interpretation

Method

Polymerase Chain Reaction (PCR)/Capillary Electrophoresis

Reference Range

See individual components

Ref. Range Notes

	Normal	Mutable Normal	Intermediate Penetrance	Full Penetrance
SCA 7	<19 repeats	28-33 repeats	34-36 repeats	>36 repeats

Ordering & Collection

Specimen Type

Blood/Cultured amniocytes or chorionic villus cells/Extracted DNA from blood, chorionic villi, and amniocyte. Direct chorionic villi, amniocyte, or amniotic fluid testing require Genetics Director approval. Please call the lab at 206-598-7021

Collection

Acceptable:

Whole blood:5 mL lavender top (EDTA) tube or yellow (ACD) top tube or 2 mL microtainer lavender top tube
Extracted DNA from blood, chorionic villi, and amniocytes: 500 ng (concentration >10 ng/uL)
Cultured amniocytes/chorionic villi: MCC is required for testing fetal samples. See MCC OLTG.
Also acceptable, but requires the Genetics Director's approval and a backup culture. Direct chorionic villi and/or TISSUE: Send 20mg of tissue in a sterile tube or RPMI culture media

*NOTE: If a fetal sample (cultured amniocytes or chorionic villi) was received, add MCC to the order. Prenatal testing requires concomitant testing for maternal cell contamination (see Online Test Guide, MCC for ordering and specimen requirements). See Special Instructions.

Unacceptable: Heparin green top tubes, buccal swab

Forms & Requisitions

Genetics Requisition

Handling Instructions

SPS specimen handling:

Whole blood sample: store in the refrigerator
Cultured amniocytes/chorionic villi: store at room temperature. Call the Genetics lab upon receipt (206)598-7021.
Extracted DNA: store in the refrigerator

Quantity

requested: Entire specimen
minimum: Blood: 1 mL. If volume is less than 1mL, do not cancel. Send to Genetics lab. Confluent cultured cells: One (1) T25 flask. Extracted DNA: 250 ng

Processing

Processing: For clients outside of UW, please include any relevant clinical history.

If fetal tissue (cultured amniocytes or chorionic villi) was received for prenatal testing, consultation with the laboratory is required. Please notify the Genetics lab about prenatal studies via email at geneticshelp@uw.edu or call 206-598-7021.

Performance

LIS Dept Code

Genetics (GEN)

Performing Location(s)

UW-MT	Genetics Attention: Genetics Lab Clinical lab, Room NW220 University of Washington Medical Center 1959 NE Pacific Street Seattle, WA 98195 Tel: 206-598–6429 M–F (7:30 AM–4:00 PM) Fax: 206-616-4584 Lab email: cgateam@uw.edu Tel (EXOME only): 206-543-0459	Faculty Jillian Buchan, PhD, FACMG Runjun Kumar, MD, PhD Regina Kwon, MD, MPH Christina Lockwood, PhD, DABCC, DABMGG Brian Shirts, MD, PhD Abbye McEwen, MD, PhD Colin Pritchard, MD, PhD Vera Paulson, MD, PhD Eric Konnick, MD, MS He Fang, PhD

Frequency

Performed weekly. Results within 2-3 weeks.

Available STAT?

Billing & Coding

CPT codes: 81181
LOINC: 49652-1