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Filaggrin (FLG) 2 Mutations
Ordering Recommendation

Confirm diagnosis of ichthyosis vulgaris and differentiate vulgaris from other forms of ichthyosis.

Polymerase Chain Reaction/Fluorescence Monitoring
7-10 days
New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
ARUP Consult®
Disease Topics
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 Filaggrin (FLG) 2 Mutations
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.
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 NameLOINC
2007884Filaggrin (FLG) 2 Mutations Specimen
2007885Filaggrin R501X
2007886Filaggrin 2282Del4
2007887Filaggrin 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 click the sidebar link to access the Interface Map.