Molecular DNA test to confirm a diagnosis of biotinidase (BTD) deficiency when biotinidase enzymatic activity is low. To diagnose or rule out BTD deficiency, refer to Biotinidase, Serum (with Paired Normal Control) (0093362).
- 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
Characteristics: Ataxia, hypotonia, developmental delay, respiratory problems, seizures, vision problems, hearing loss, alopecia, rash, candidiasis, metabolic ketolactic acidosis, organic aciduria and mild hyperammonemia.
Incidence: 1 in 60,000.
Inheritance: Autosomal recessive.
Cause: Deleterious BTD gene mutations.
Clinical Sensitivity: 99 percent.
Methodology: Bidirectional sequencing of the entire BTD coding region and intron-exon boundaries.
Analytical Sensitivity & 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.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|0051731||Biotinidase Deficiency (BTD) Sequencing|
|2001339||BTD FGS Specimen|
- BTD mutation testing