Genetics of Connexin 26 Deafness Research

Most of the congenital deafness in the worldwide deaf community is caused by mutations in the connexin 26 (GJB2) gene. Even though there are over 100 genes associated with deafness, mutations in connexin 26 alone are disproportionately responsible for 35-50 percent of congenital deafness, depending upon the population.

This unexpectedly high prevalence of connexin 26 mutations begs the question: is there a genetic or perhaps an evolutionary mechanism driving its current prevalence in our population?

Dr. Braun is using molecular and bioinformatic methods to reconstruct the genealogy of the connexin 26 mutations. Among the hypotheses which he is testing are whether connexin 26 is under relaxed selection and whether recent intermarriage between deaf individuals, arising from meeting one another at residential schools for the deaf, has increased the prevalence of connexin 26 deafness.

This project is part of an ongoing collaboration with Dr. Kathy Arnos of the Biology Department, who established the Genetics Program at Gallaudet in 1982; Dr. Arti Pandya and Dr. Walter Nance at Virginia Commonwealth University; and Dr. Mustafa Tekin at the University of Miami and Ankara University in Turkey.

Students performing research with Dr. Braun routinely perform molecular genetics methods including –

• polymerase chain reactions (PCR)
• agarose gel electrophoresis
• molecular cloning
• growing and handling E. coli cultures
• mini-preparations of plasmid DNA
• preparation of DNA samples for sequencing

We also utilize bioinformatics approaches such as computational/statistical analyses of our sequence datasets using available tools and programs, including the popular, high-level programming language Python.