Comprehensive Genetic Testing for Deafness from Fresh and Archived Dried Blood Spots

Comprehensive genetic testing has become integral in the evaluation of children with deafness, but the amount of blood required to obtain DNA can be prohibitive in newborns. Dried blood spots (DBSs) are routinely collected and would provide an alternative source of DNA. Our objective was to evaluate the use of DBSs for comprehensive genetic testing for deafness. DNA derived from fresh and archived DBS samples was compared with DNA from whole blood. We performed next-generation sequencing of all known deafness genes in 4 DBS samples: 2 positive controls, an unknown sample, and a negative control. The DBS-derived DNA was of sufficient quantity and quality for clinical testing. In the 2 positive control samples, pathogenic variants were identified; in the negative control, no pathogenic variants were found; and in the unknown sample, homozygous deletion of the OTOA gene was identified as the cause of deafness. This pilot study shows that comprehensive genetic testing for deafness is feasible with fresh and/or archived DBSs.