Research led by the Children’s Hospital of Fudan in Shanghai shows that adding a genomic screening panel to testing for newborn hearing loss could improve accuracy of screening and allow affected children to get the help they need at an early stage.
Affecting up to 0.3% of healthy babies and up to 4% of babies admitted to the neonatal intensive care unit (NICU), hearing loss is a common problem and the fourth major cause of disability.
It is important to identify hearing loss early. Depending on the cause, identification and treatment can slow or even prevent further damage and can also help prevent issues associated with unidentified hearing loss such as problems with language and social-emotional development.
“Currently, the most cost-effective approach to prevent hearing loss is early screening and identification of the cause,” write Bingbing Wu and Zhengmin Xu, both based at the Children’s Hospital of Fudan, and colleagues in the journal JAMA Network Open.
“Previous studies have shown that approximately 25% of cases of hearing loss are missed by existing newborn hearing screening programs, wherein two-thirds receive a diagnosis of severe to profound hearing loss later.”
Hearing loss is caused by multiple different clinical factors including cytomegalovirus infection, oxygen exposure, craniofacial malformation and many other environmental factors, but genetics also plays a strong role.
Some limited genetic testing has been carried out in the past, but the impact of more extensive expanded genomic sequencing on the accuracy of hearing loss screening has not been extensively investigated.
To assess the value of this type of genomic screening, particularly for higher risk babies in the NICU, the researchers enrolled 8078 newborns for testing (aged 3 to 12 days) who were admitted to the Children’s Hospital of Fudan University between 2016 and 2020. All the participants had a standard hearing test and a genomic screen including 2742 genes linked to hearing loss. Follow up to assess hearing status was carried out in late 2021.
Using standard testing, 52 children received a diagnosis of hearing loss, 39 of whom also had genetic variants linked to hearing loss. Genomic testing identified a further 7 at-risk children who were missed by standard testing.
Variants in the genes GJB2 and SLC26A4 were the most common in the group with hearing loss. Children who had genetic variants linked to hearing loss had more severe symptoms than those who did not.
Ahmad Abou Tayoun, from Al Jalila Children’s Specialty Hospital, Dubai, contributed a commentary article in the same journal. He applauds the study, but points out that mutations were identified in only 15 of the 2742 genes included in the genomic testing. “This information has important implications for the implementation of a cost-effective and highly sensitive, targeted genetic hearing loss screening approach specific to this population,” he writes. “Although the cost of expanded sequencing continues to decrease, it is still prohibitive for population-based newborn screening.”
He also notes that the genetic screen may have the advantage of identifying children with mild and later-onset hearing loss.
“However, additional work is needed to characterize the genetic landscape of hearing loss across populations and to define the optimal population-wide genetic screening method for deafness,” he concludes.