Usher Syndrome Subpanel
Usher syndrome is a genetically heterogeneous condition characterized by the association of retinitis pigmentosa with sensorineural deafness. Age at onset and differences in auditory and vestibular function distinguish Usher syndrome type 1 (USH1), Usher syndrome type 2 (USH2) and Usher syndrome type 3 (USH3). USH1 has an age of onset in childhood, whereas USH3 often begins in adolescence.
The Usher Syndrome Subpanel includes 11 genes. Our customizable targeted next-generation sequencing (NGS) panel uses Agilent SureSelect™ target enrichment and Illumina HiSeq sequencing. NGS technology is ideal for diagnostic testing of these disorders due to the extreme locus heterogeneity and phenotype overlap of the genes involved. The sensitivity of this panel is estimated at 99% for single-base substitutions.
If indicated, Sanger sequencing may be performed in both directions using BigDye Terminator chemistry with the ABI 3730 DNA analyzer with target specific amplicons. It may also be used to supplement specific guaranteed target regions that fail NGS sequencing or as a confirmatory method for NGS positive results. NGS technology may not detect all small insertions or deletions. Additionally, it is not diagnostic for large duplications or deletions, repeat expansions, and structural genomic variation. Therefore, multiplex ligation-dependent probe amplification (MLPA) and oligonucleotide array comparative genomic hybridization (aCGH) are available for this test for deletion/duplication analysis. MLPA copy number analysis is available for the DFNB1 (GJB2/GJB6) locus, OTOA, and STRC. This MLPA testing is approximately 99% accurate. The customized oligonucleotide microarray is a highly-targeted, exon-focused array capable of detecting microdeletions and microduplications at a much higher resolution than traditional aCGH methods. The sensitivity of the aCGH assay is estimated to be greater than 99% for medically-relevant microdeletions and microduplications in the exonic regions of 11 genes.
Specimen Requirements
Prenatal
Please provide one of the following specimen types:
- Two confluent T-25 flasks of cultured cells from amniotic fluid or chorionic villi
- >4 mg of direct chorionic villi tissue
- 15 mL of direct amniotic fluid
5-10 mL of blood in an EDTA tube (lavender top) is required from each biological parent. Parental blood samples may be used for maternal cell contamination studies or confirmation studies.
Whole blood
- One 2 mL EDTA tube (lavender top) or one 2 mL ACD-A or ACD-B tube (yellow top) from the patient
- One 5-10 mL EDTA tube (lavender top) or one 5-10 mL ACD-A or ACD-B tube (yellow top) is also recommended from each biological parent
Adult
- Two 5-10 mL EDTA tubes (lavender top) or two 5-10 mL ACD-A or ACD-B tubes (yellow top) from the patient
- One 5-10 mL EDTA tube (lavender top) or one 5-10 mL ACD-A or ACD-B tube (yellow top) is also recommended from each biological parent
Extracted DNA
- A minimum of 10 μL DNA (50-250 ng/μL) is required for testing. 20 μL DNA (50-350 ng/μL) is recommended
Saliva
- Saliva specimens are accepted upon request. Please contact our laboratory to obtain saliva kits
- Saliva samples should be collected in Oragene DNA (OG-500) kits by DNA Genotek
Ordering Information
Shipping
- Tubes of blood, cultured cells, direct chorionic villus sampling, and direct amniotic fluid should be stored and shipped at room temperature or refrigerated
- Do not freeze specimens
- Please ship specimens same day or overnight to: 62 Southfield Ave, Stamford, CT 06902
Turnaround Time
- Prenatal: 7-10 business days from receipt of specimen
- Pediatric or adult: 3-4 weeks from receipt of specimen
Related Tests
Resources
Hearing and Vision Loss Test Requisition
Genetic Testing for Hearing and Vision Loss Brochure
