Article
Results of our non-syndromic hearing loss genetic screening program
Ergebnisse unseres nicht-syndromischen Hörverlust screening Programms
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Authors
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Attila L. Nagy
- University of Szeged, Department of Otorhinolaryngology, Head and Neck Surgery, Szeged, Hungary
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Róbert Csáki
- Alfa-Biosoft Ltd., Szeged, Hungary
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József Klem
- University of Szeged, Department of Biotechnology, Szeged, Hungary
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Miklós Csanády
- University of Szeged, Department of Otorhinolaryngology, Head and Neck Surgery, Szeged, Hungary
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Ferenc Tóth
- University of Szeged, Department of Otorhinolaryngology, Head and Neck Surgery, Szeged, Hungary
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Attila Torkos
- University of Szeged, Department of Otorhinolaryngology, Head and Neck Surgery, Szeged, Hungary
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Kornél Kovács
- University of Szeged, Department of Biotechnology, Szeged, Hungary
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József Jóri
- University of Szeged, Department of Otorhinolaryngology, Head and Neck Surgery, Szeged, Hungary
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József Géza Kiss
- University of Szeged, Department of Otorhinolaryngology, Head and Neck Surgery, Szeged, Hungary
| Published: | September 7, 2006 |
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Outline
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Problem: Non-syndromic hearing loss is one of the most abundant human sensory disorders, and can be found in 1 out of 1000 newborns. In 60-70 percent of the cases this disorder is hereditary, and in 70-80 percent of the cases has autosomal recessive genotype. The phenotype varies from moderate hearing loss to almost complete deafness, and, sometimes its expression occurs only in late childhood, meaning that traditional methods to improve hearing, and more importantly speech understanding and reproduction, can be applied with less success.
If we could detect these genetic variations early enough, perinatally, for example, or in the first few weeks of life, then we can plan the audiological and logopedical procedures to maintain the children's normal audiological and speech development, if needed with a planned, and just in time implemented cochlear implantation. We plan to detect more point mutations at once as we progress with our experiments.
Methods: We collect blood from patients with probable hereditary hearing loss, or deafness. Control blood samples are being collected from subjects with intact auditory system. The blood is collected into anti-coagulant tubes. DNA is cleaned from the samples with Viogen Blood DNA kit. We planned primer pairs to carry out AS-PCR reactions on the samples. In the first turn we analysed our samples looking for 35delG mutation in the GJB2 (Cx26) gene, which is one of the most abundant mutations that cause non-syndromic hearing loss.
Results: We found numerous patients with 35delG mutations, both heterozygous (with no detected hearing – related phenotypical discrepancies), and homozigous (phenotipically with moderate – to severe hearing loss) forms.
Conclusions: The methods work, the alterations we studied so far, can be detected in our group of patients. The next steps will provide us information on the possibilities of genetic screening in this field. The ongoing project, if completed successfully, can provide a tool that allows us to detect more genetic point mutations at one time, which can be of help when no other signs of possible hearing defects are detectable, but the suspicion exists.
