Creatine Transporter Deficiency (SLC6A8) Sequencing
Ordering Recommendation

Molecular 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).

Polymerase Chain Reaction/Sequencing
21-28 days
New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable 
Reference Interval
By report
Interpretive Data
Background Information for Creatine Transporter Deficiency (SLC6A8) Sequencing:
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.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations, deep intronic mutations, and large deletions/duplications will not be detected. Mutations in genes other than SLC6A8 were not evaluated.

Statement C: Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Hotline History
Component Test Code*Component Chart NameLOINC
2008616SLC6A8 Seq Specimen
2008617SLC6A8 Seq 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 view this test within the Laboratory Test Directory found at