Dry test: detection of the 35delG Connexin26 gene mutation responsible for autosomal recessive nonsyndromic hearing loss from dry blood sample

This test is designed to detect the most frequent 35delG mutation of the Connexin26 gene (GJB2), with a frequency >90% of all pathological mutations of this particular gene and a carrier frequency in the general population of about 3% (1 out of 30).

In case the presence of the 35delG mutation is detected in the maternal blood sample, an immediate and comprehensive mutation analysis of this disorder from a paternal blood sample is necessary, in order to evaluate the risk for the fetus. This particularly useful test affords the detection of a large percentage of carriers for the disorder and will reveal couples at-risk, early in pregnancy.

It is applied from a maternal dry blood sample during pregnancy and as a complementary test to: Risk for Down syndrome using biochemical markers from dry blood samples (1st and 2nd trimester of pregnancy).

Samples should be collected using the special cards provided. Instructions for sampling procedures are printed at the back of the card. After the blood sample has completely dried up, it may be stored dry in an envelope, at room temperature.

For longer periods and during the warm months of the year, it is advised to store the sample at 4°C (in a commercial/household refrigerator). Shipment should be made by mail or courier service.

** Detection of the 35delG mutation does NOT CONSTITUTE a full mutation analysis for autosomal recessive hearing loss.