AR deafness – detection of 35delG GJB2 mutation

Clinical expertise code:

208

Test without reimbursement:

YES

Gender:

Woman/Man

Material:

Peripheral blood, Isolated DNA from blood

Turnover time:

3 weeks

STATIM:

3 days

Material:

Peripheral blood | 1x 3 ml of whole blood in K3 EDTA tube

Storage after examination: week after the report is issued 2 – 8°C

Isolated DNA from blood | 10–100 ng/μL of isolated DNA from blood in a PCR tube of at least 15 μL.

Storage after examination: stored in a DNA archive without restriction 15°C

Quick test description:

Testing for 35delG mutation in the GJB2 gene responsible for AR hereditary, non-syndromic disorder/hearing loss (deafness).

Test details:

The test is performed to detect 35delG mutation in the GJB2 gene.

GJB2 (gap junction beta 2) gene mutations are responsible for hereditary autosomal recessive disease – early non-syndromic disorder/hearing loss and deafness, also referred to as DFNB1, with an approximate incidence of 1:5,000 live births. Hearing loss in those affected is always perceptual (sensorineural) and prelingual (early) – before speech development. In the Czech population, the 35delG mutation is prevalent (80% of pathogenic alleles).

Testing for the del35G mutation in the GJB2 gene is performed by real-time PCR, which is based on amplification of the DNA sequence of the corresponding region. Using real-time PCR technology, it is possible to determine the amount of PCR product generated by recording the fluorescence signal generated during the reaction (in real time). Two independent fluorescent signals are generated in each tube, on the basis of which the test result is determined. Each fluorescent signal is associated with an allele type, from which homozygous (MUT), heterozygous for mutation (HET) or homozygous without mutation (WT) can be distinguished.

Indication

Vrozená prelinguální ztráta sluchu, vrozená prelinguální ztráta sluchu v rodině, vyšetření vrozené ztráty sluchu před kochleární implantací, testování přítomnosti mutace u partnerů v příbuzenském svazku, popř. u novorozenců narozených z incestních vztahů, vyšetřování slyšících příbuzných v rodinách, kde již byla mutace GJB2 zjištěna, u partnera nosiče mutace GJB2 před plánovaným těhotenstvím, případně v průběhu těhotenství, vyšetření dárců gamet

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