The Usher Syndrome Panel is a comprehensive next-generation sequencing (NGS) panel that can be used to confirm a clinical diagnosis of Usher syndrome or identify at-risk individuals.
Usher syndrome is characterized by hearing loss that is typically present from birth, and progressive vision loss. There are three subtypes of Usher syndrome, with varying ages of onset and severity of hearing and vision loss. Individuals with Usher syndrome type 1 have profound congenital deafness and onset of progressive retinitis pigmentosa before puberty. Usher syndrome type 2 involves severe to profound deafness and later onset of retinitis pigmentosa, while Usher syndrome type 3 demonstrates later onset of both deafness and vision loss. Individuals with Usher syndrome may also have vestibular anomalies, which affects balance and space perception.
This panel includes genes associated with:
- Usher syndrome
- Retinitis pigmentosa
- Charcot-Marie-Tooth disease
- Cone-rod dystrophy
- Nonsyndromic hearing loss and deafness
The combined prevalence of all forms of Usher syndrome is 1 in 6,000 individuals (Kimberling et al, 2010), although it may be higher in some populations.
Inheritance and Penetrance
Usher syndrome is inherited in an autosomal recessive fashion, and is typically fully penetrant.
Disease causing variants can be identified in approximately 90% of Usher syndrome cases (Bolz and Roux, 2011). The Usher Syndrome Panel includes all of the common genetic causes related to this disease.
Methodology and Analytical Sensitivity
Next-generation sequencing technology is used to test clinically relevant portions of each gene, including coding exons, adjacent flanking bases, and selected introns/noncoding variants. Pathogenic and likely pathogenic variants are confirmed by orthogonal methods. Copy number variants, including intragenic deletions and duplications are detected to a resolution of a single exon. To request analysis of a specific single exon copy number variant, please contact our Client Services team prior to ordering. Analytical sensitivity and specificity of the assay is >99%.
Indications for Testing
- Confirmation of a clinical diagnosis
- Individuals with deafness and blindness
- Risk assessment for asymptomatic family members of proband with molecular diagnosis of Usher syndrome
Included Genes (13)
- Bolz HJ, Roux AF. Clinical utility gene card for: Usher syndrome. Eur J Hum Genet. 2011;19(8)
- Kimberling WJ, Hildebrand MS, Shearer AE, et al. Frequency of Usher syndrome in two pediatric populations: Implications for genetic screening of deaf and hard of hearing children. Genet Med. 2010;12(8):512-6.