Confirm diagnosis of ichthyosis vulgaris and differentiate vulgaris from other forms of ichthyosis.
- 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: Two mutations in the FLG gene, c.1501C>T (R501X) and c.2282del4, are associated with ichthyosis vulgaris, keratosis pilaris and an increased risk for atopic disease, including atopic dermatitis (eczema), allergic rhinitis and asthma.
Incidence: Approximately 7-10 percent of Caucasian individuals have one or more mutations in the FLG gene.
Inheritance: Autosomal dominant with reduced penetrance.
Penetrance: 100 percent in individuals with two FLG loss-of-function mutations and approximately 88 percent in those with one mutation, though severity of symptoms is highly variable. Some individuals may be asymptomatic.
Cause: The presence of at least one pathogenic FLG gene mutation. Mutations in other genes may also be causative.
Mutations Tested:FLG gene mutations c.1501C>T (R501X) and c.2282del4.
Clinical Sensitivity: Estimated to be 80 percent in Caucasians.
Methodology: Multiplex PCR followed by fluorescent monitoring using hybridization probes.
Analytical Sensitivity and Specificity: 99 percent.
Limitations:FLG mutations other than c.1501C>T (R501X) and c.2282del4 will not be evaluated. Diagnostic errors can occur due to rare sequence variations.
|Component Test Code*||Component Chart Name||LOINC|
|2007884||Filaggrin (FLG) 2 Mutations Specimen|