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).
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 2 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
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.
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.
|Component Test Code*||Component Chart Name||LOINC|
|2008611||SLC6A8 Seq/DelDup Specimen|
|2008612||SLC6A8 Seq/DelDup Interpretation|