Ordering Recommendation

Carrier screening or diagnostic testing for Usher syndrome types 1F and 3 for individuals of Ashkenazi Jewish descent.




Polymerase Chain Reaction/Fluorescence Monitoring


Tue, Fri


5-10 days

New York DOH Approval Status

This test is New York DOH approved.

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

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:
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.

Compliance Category

Laboratory Developed Test (LDT)


Hotline History


CPT Codes



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
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Usher Syndrome, Types 1F and 3 (PCDH15 and CLRN1), 2 Variants