The future of audiology – genomic newborn hearing screening

Did you know one in 500 newborns has hearing loss?

Newborn screening can identify deafness which is present at birth. Early detection is vital. Babies with hearing loss or deafness experience the greatest benefits when interventions (speech-language therapy, sign language, or hearing aids) begin by six months of age.

Despite the many successes of universal newborn hearing screening, traditional screening methods have limitations. This includes high false-positive and false-negative rates, and in some instances the inability to prevent hearing loss before symptoms appear. However, new advances in DNA sequencing (genomics) and computing technologies have enabled rapid discoveries of genetic causes of hearing loss.

Why is genetic screening for deafness so important?

• Accurate genetic diagnosis helps guide the best course of possible intervention and treatment. Genetic information can predict the likely course of hearing loss (prognosis) and determine the best management and rehabilitation option. Hearing aids, cochlear implants, auditory brainstem implants, and sign language are currently available to manage hearing loss. The best choice and outcome for management depends upon the underlying cause and timing of intervention. As more connections are being catalogued between genes and deafness, genetic diagnosis will provide precise diagnoses and prognoses to inform appropriate interventions.
• Genetic diagnosis of hearing loss in pre-symptomatic patients can allow careful monitoring to catch the optimal therapeutic window for hearing loss or other associated complications as well as minimize environmental hazards that can worsen hearing.
• Definitive genetic test results can, in many cases, eliminate the need for other expensive, uncomfortable or even harmful diagnostic tests that, for instance, require the use of sedatives or exposure to radiation in young children.
• Genetic information can inform recurrence risks to family members and future children. The information is particularly useful in cases where the hearing loss or associated features are not readily detectable during early childhood.

What are the next steps underway in Manchester?

At Manchester BRC we are embarking on a study, SEQaBOO (SEQuencing a Baby for an Optimal Outcome) Manchester, to implement genome sequencing into newborn hearing screening. Presently, because newborn hearing screening doesn’t include any form of genetic testing, identification of heritable deafness goes undiagnosed and, at best, is delayed. Sequencing can help to explain the genetic cause regardless of clinical findings, translating into opportunities for optimal management at the earliest possible time.

While standard newborn screening techniques are effective at detecting the absence of hearing, they don’t account for each baby’s unique genetic makeup, which may affect how well a therapy or strategy works for them.

Current research supports a critical need for a clinical genomics application to identify the genetic and molecular causes of hearing loss. Next-generation genomic newborn hearing screening is predicted to become the routine of public health care in the future just as the current newborn hearing screening programme is today.

Newborn hearing screening has benefited so many infants. But, it’s time to address recognised limitations of the screen and identify infants missed, to provide them with the opportunity for life-altering treatments and benefits. We must move forward now to incorporate new genomic technologies – these babies deserve nothing less from us.

Genomics has the potential for fantastic improvements in prevention, health protection and patient outcomes. Through genomics we’ll know the ‘recipe’ for why some of our body doesn’t work as well as it should. We’ll be using the sequencing information to understand why a metabolic pathway or developmental pathway doesn’t work correctly. Knowing that, we can harness the information to guide development of drugs and other approaches to treat deafness.

Until recently, in the last five years, except for drug therapies I had never thought about ‘curing’ deafness. While I do appreciate that not everybody wants to be ‘cured’ of their deafness some people do, and they should have a choice if it’s possible.

 

Manchester BRC Hearing Health will be hosting a showcase in Manchester in October to share the work of the Hearing Health theme.