Characteristics of the test: (includes 1 gene)
USH2A (OMIM#608400)

Basic characteristics of the clinical phenotype:
Usher syndrome is an autosomal recessive disorder characterized by hearing impairment, progressive retinal degeneration and, in some cases, vestibular dysfunction. This syndrome is the most common cause of simultaneous hearing and vision loss, accounting for over 50% of patients, affecting between 1:12,000 and 1:30,000 individuals for different populations worldwide. Three forms of Usher syndrome are known, and the clinical picture is distinguished based on the onset of the disease, severity of symptoms and involvement of the vestibular apparatus.

Basic characteristics of the clinical phenotype:
Usher syndrome type 2 (USH2 OMIM #276901) is characterized by moderate to severe congenital hearing loss, retinal degeneration (RP) with teenage onset, and normal vestibular function. The clinical feature of RP includes night blindness progressing to narrowing of the peripheral visual field with eventual loss of central vision, an abnormal fundus with pigment deposits and narrowed retinal vessels, and an electroretinogram (ERG) ordered.

Reasons for referring:
All patients with congenital hearing loss and retinal pigment degeneration but without vestibular function impairment.

Interpretation of results:

· Detection of deletions/duplications/rearrangements in the USH2A gene allows the diagnosis of Hereditary Adenomatous Polyposis (FAP).
· The genetic counselor will interpret and answer all questions about your result.

Method: MLPA (Multiplex Ligation Dependent Probe Amplification)
MLPA is a semi-quantitative method for determining DNA copy number variations. The methodology is used to detect intragenic or whole-gene deletions or duplications.

Sensitivity of the method: 90%

What does the test involve?
· DNA isolation and sample storage.
· MLPA to detect deletions/duplications that affect the Usher syndrome gene.
· MLPA probes for the presence of specific known point mutations in the MUTYH gene (c.536A>G, ​​p.Tyr179Cys and c.1187G>A, p.Gly396Asp).
· Forming a written result of the genetic test.
· Diagnostic interpretation of results and genetic counseling.
Sensitivity of the method: 99.5%

Biological material: Venous blood or DNA
For more information, please read the "Biological material requirements and shipping information" carefully.