Ordering Recommendation
Carrier screening or diagnostic testing for Usher syndrome types 1F and 3 for individuals of Ashkenazi Jewish descent.
Mnemonic
Methodology
Polymerase Chain Reaction/Fluorescence Monitoring
Performed
Tue, Fri
Reported
5-10 days
New York DOH Approval Status
Specimen Required
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 1 mL)
Refrigerated.
Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes. Frozen specimens in glass collection tubes.
Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month
Reference Interval
By report
Interpretive Data
Background Information for Usher Syndrome, Types 1F and 3 (PCDH15 and CLRN1), 2 Variants:
Characteristics: Usher syndrome type 1F is characterized by congenital, bilateral, profound sensorineural hearing loss, adolescent-onset retinitis pigmentosa and loss of vestibular function. Usher syndrome type 3 is characterized by post-lingual, progressive hearing loss, late-onset progressive vision loss due to retinitis pigmentosa and variable loss of vestibular function.
Incidence: In Ashkenazi Jewish individuals - 1 in 20,500 for Usher syndrome type 1F; 1 in 82,000 for Usher syndrome type 3.
Inheritance: Autosomal recessive.
Cause: PCDH15 and CLRN1 pathogenic variants.
Variants Tested: PCDH15 p.R245X (c.733C>T), CLRN1 p.N48K (c.144T>G).
Clinical Sensitivity: In Ashkenazi Jewish individuals - 62 percent for Usher syndrome, type 1F; 98 percent for Usher syndrome, type 3. Sensitivities unknown in other ethnicities.
Methodology: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Variants other than those tested will not be detected. Diagnostic errors can occur due to rare sequence variations.
Laboratory Developed Test (LDT)
Note
Hotline History
Hotline History
CPT Codes
81400
Components
Component Test Code* | Component Chart Name | LOINC |
---|---|---|
2013751 | Usher Syndrome Types 1F and 3, Specimen | |
2013752 | Usher Syndrome Types 1F and 3, Allele 1 | |
2013753 | Usher Syndrome Types 1F and 3, Allele 2 | |
2013754 | Usher Syndrome Types 1F and 3, Interp |