Characteristics of the test: (includes 42 genes)

Basic characteristics of the clinical phenotype:

Cone-rod retinal dystrophy (COD/CORD) is a rare hereditary disease with an incidence of approximately 1:40,000 worldwide. In cone dystrophies (COD), the functional deficit is limited to the daytime vision system (the cones). In other forms of cone dystrophies (probably the majority), symptoms of rod dystrophy (CORD) also appear later in the course of the disease.

COD and CORD are nonprogressive and progressive according to the course of the disease, and according to the type of inheritance they are distinguished as autosomal recessive (ar), autosomal dominant (ad) and X-linked (Xl). This type of retinal dystrophy is most often non-syndromic, but can also be part of several syndromes, such as Bardet-Beidle syndrome (BBS)

The main genes with a role in the pathogenesis of CORDs are 4 and include: CRX and GUCY2D (mutations in these lead to autosomal dominant forms of CORDs), ABCA4 (which, in addition to Stargardt disease, is also responsible for 30-60% of the cases with autosomal recessive CORDs) and RPGR (which is responsible for X-linked CORDs).

Reasons for referring:

All patients with symptoms of cone-rod retinal dystrophy (COD/CORD). This test is offered to patients in whom no mutations have been found.

Interpretation of results:
· The detection of point mutations and small deletions/insertions in the genes from the panel will allow a genetic diagnosis of cone-rod dystrophy (COD/CОRD).
· Presence of large deletions and insertions cannot be detected by this method. A combination with a suitable CNV analysis (MLPA, aCGH) is recommended for their detection.
· The genetic counselor will interpret and answer all questions about your result.

Method: Next-generation sequencing.
The method involves bi-directional DNA sequencing of all coding exons and intron-exon boundaries of the target genes. The laboratory offers Sanger sequencing of a single exon or a pair of exons in the patient's relatives to determine the carrier status in cases where the mutation is known (Test #182).

Sensitivity of the method: depends on the content of GC and AT, as well as the presence of segmentally duplicated genes.

What does the test involve?
· DNA isolation and sample storage.
· Parallel sequencing of target genes.
· Bioinformatic analysis of sequencing data. For each patient, only data for the gene(s) of interest were analyzed.
· Forming a written result of the genetic test.
· Diagnostic interpretation of results and genetic counseling.

Biological material: Venous blood or DNA

For more information, please read the "Biological material requirements and shipping information" carefully.