In Russia, there is a pathway to address hereditary hearing loss during embryonic development, though many families where both parents are deaf feel hesitant to pursue it due to concerns about losing contact with their child. A molecular geneticist and a vice-rector for scientific work at a major national university discussed this development with a journalist from socialbites.ca, highlighting the work of a leading translational medicine institute.
The scientist explains that every person has two complete sets of genes, one inherited from each parent. If one gene is defective but the other functions normally, the resulting condition does not typically manifest.
However, if both copies of a gene are defective, the odds shift. The chance of such a pairing occurring is around one percent, a figure that remains significant. If both parents carry a hereditary disease, such as hereditary hearing loss, there is a 100 percent likelihood that their children will inherit the same condition. This happens because, in these families, a healthy version of the gene is not present to be passed on, and the faulty gene is inherited in both parental lines, leading to a predictable outcome for each child.
The experts note that scientists in Russia have developed a technology aimed at helping such couples have healthy children.
According to the researchers, a CRISPR/Cas-based approach enables gene repair at the very first stage of embryonic development. The process involves examining the zygote, the initial cell that forms after fertilization, and correcting the defective parental gene within it. This intervention could enable the birth of a healthy baby. Yet, there is a specific ethical and social consideration for families where hearing loss is prevalent; the number of couples willing to pursue this option remains limited, with estimates ranging from two hundred to five hundred individuals with hearing loss in Russia who have expressed interest.
Experts note that concerns among these families center on the potential impact on family dynamics, including the fear that a hearing child might drift away from deaf parents or leave the family environment.
For couples affected by hereditary hearing loss due to the Connexin 26 gene (GJB2), a pathway exists for genetic consultation and, after thorough genetic screening, submission of documentation to relevant health authorities to consider employing this approach. The researchers express confidence that progress will continue in this area.
Earlier work by other scientists showed that reversing hearing loss in animal models could be achieved by activating specific genetic pathways, illustrating the potential for gene-based therapies to modify sensory conditions in the future.