Preferred molecular (DNA) test to confirm a diagnosis of primary carnitine deficiency following clinical and/or biochemical presentation. To diagnose or rule out primary carnitine deficiency, refer to Carnitine, Free & Total (Includes Carnitine, Esterified) (0080068) and Carnitine, Free and Total, Urine (0081308).
Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 2 mL)
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Background information for Primary Carnitine Deficiency (SLC22A5) Sequencing and Deletion/Duplication:
Characteristics: Hypoketotic hypoglycemia during periods of fasting, hepatomegaly, Reye syndrome, sudden infant death, developmental delay, cardiac and/or skeletal myopathy, hypotonia and enlarged heart.
Incidence: 1 in 40,000 for European Caucasian and Japanese, lower in other populations.
Inheritance: Autosomal recessive.
Cause: Pathogenic SLC22A5 gene mutations.
Clinical Sensitivity: May be as high as 95 percent.
Methodology: Bidirectional sequencing of the entire coding region and intron-exon boundaries of SLC22A5 gene; Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large SLC22A5 coding region deletions/duplications.
Analytical Sensitivity: Greater than 99 percent.
Limitations: Mutations in genes other than SLC22A5 will not be detected; deletion/duplication breakpoints will not be determined; deep intronic mutations and promoter mutations in the SLC22A5 gene will not be detected. Mutations within the primer/probe regions could affect the analytical sensitivity of this assay. Diagnostic errors can occur due to rare sequence variations.
Laboratory Developed Test (LDT)
|Component Test Code*||Component Chart Name||LOINC|
|2004204||PCD FGA Specimen|
|2004205||Primary Carnitine Deficiency Interpretat|
- Carnitine Deficiency
- SLC22A5 sequencing and deletion/duplication assay