Usher Syndrome: Sequencing Panel

Create a PDF of this page

Condition Description

Usher syndrome is a disorder consisting of retinitis pigmentosa (RP) and congenital hearing loss, ranging from partial or profound. Several clinical subtypes exist. Usher syndrome type I is generally characterized by profound congenital hearing loss with no vestibular function and early onset RP. Usher syndrome type II is generally characterized by mild to severe pre-lingual hearing loss with intact vestibular function and adolescent or adult onset RP. Usher syndrome type III is characterized by progressive post-lingual hearing loss, variable vestibular impairment, and late onset RP.

References:  
  • Daiger et al. (1998) Invest Ophthalmol Vis Sci 39:S295.
  • OMIM
  • GeneReviews
  • Emory and Rimoin's Principles and Practice of Medical Genetics, 5th Edition

Genes (12)

Indications

This test is indicated for:
  • Confirmation of a clinical diagnosis of Usher syndrome.
  • Carrier testing in adults with a family history of Usher syndrome.

Methodology

Next Generation Sequencing: In-solution hybridization of all coding exons is performed on the patient's genomic DNA. Although some deep intronic regions may also be analyzed, this assay is not meant to interrogate most promoter regions, deep intronic regions, or other regulatory elements, and does not detect single or multi-exon deletions or duplications. Direct sequencing of the captured regions is performed using next generation sequencing. The patient's gene sequences are then compared to a standard reference sequence. Potentially causative variants and areas of low coverage are Sanger-sequenced. Sequence variations are classified as pathogenic, likely pathogenic, benign, likely benign, or variants of unknown significance. Variants of unknown significance may require further studies of the patient and/or family members.

Detection

Clinical Sensitivity: Unknown. Pathogenic variants in the promoter region, some pathogenic variants in the introns and other regulatory element pathogenic variants cannot be detected by this analysis. Large deletions will not be detected by this analysis. Results of molecular analysis should be interpreted in the context of the patient's clinical and/or biochemical phenotype.
Analytical Sensitivity:
~99%

Specimen Requirements

Submit only 1 of the following specimen types

Type: Whole Blood

Specimen Requirements:

In EDTA (purple top) tube:
Infants (<2 years): 2-3 ml
Children (>2 years): 3-5 ml
Older Children & Adults: 5-10 ml

Specimen Collection and Shipping: Ship sample at room temperature with overnight delivery.

Type: Isolated DNA

Specimen Requirements:

In microtainer: 60 ug

Isolation using the QiagenTM Puregene kit for DNA extraction is recommended.

Specimen Collection and Shipping: Refrigerate until time of shipment in 100 ng/ul of TE buffer. Ship sample at room temperature with overnight delivery.

Special Instructions

Please include fundus photographs, electroretinogram (ERG) findings, visual field findings, and visual acuity, if available, for expert review and clinical correlation with test results.
  • Eye Disorders: Comprehensive Sequencing  and Deletion/Duplication Panels
  • Usher Syndrome: Deletion/Duplication Panel

How to Order