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Creatine Transporter Deficiency (SLC6A8) Sequencing and Deletion/Duplication
2008610
Ordering Recommendation

Preferred molecular (DNA) test to confirm a diagnosis of creatine transporter deficiency syndrome following clinical and biochemical presentation. To diagnose or rule out creatine deficiency syndromes, refer to Creatine Disorders Panel, Plasma or Serum (2002328), and Creatine Disorders Panel, Urine (2002333).

Mnemonic
SLC6A8 FGA
Methodology
Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification
Performed
Varies
Reported
28-35 days
New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 2 mL) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
 
Remarks
 
Stability
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable 
Reference Interval
By report
Interpretive Data
Background Information for Creatine Transporter Deficiency (SLC6A8) Sequencing and Deletion/Duplication:
Characteristics:
Intellectual disability and seizure disorder of variable severity. May also include speech/language delays, movement disorder, and behavioral disorders such as autism, hyperactivity, and self-injury.
Incidence:
Unknown. More than 100 cases have been described.
Inheritance:
X-linked.
Cause:
Pathogenic SLC6A8 gene mutations.
Clinical Sensitivity:
Approximately 99 percent.
Methodology:
Bidirectional sequencing of the entire coding region and intron-exon boundaries of the SLC6A8 gene. Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large SLC6A8 coding region deletions/duplications.
Analytical Sensitivity and Specificity
: 99 percent.
Limitations:
Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations and deep intronic mutations will not be detected; deletion/duplication breakpoints will not be determined. Mutations in genes other than SLC6A8 were not evaluated. Deletions/duplications in exons 2, 3, 5, 7, and 13 will not be detected.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

Compliance Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing. Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Note
CPT Code(s)
81479 x2
Components
Component Test Code*Component Chart NameLOINC
2008611SLC6A8 Seq/DelDup Specimen
2008612SLC6A8 Seq/DelDup Interpretation
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases