Characterization of Sensorineural Hearing Loss in Neurofibromatosis Type 2

Key Words: Neurofibromatosis Type 2, Vestibular Schwannoma, Schwann Cells, Dysmyelination, Synaptopathy, Macrophages, scRNAseq, Sensorineural Hearing Loss

Neurofibromatosis Type 2 (NF2) is a rare genetic condition where non-cancerous Schwann cell tumors develop along the balance portion of the hearing and balance nerve in both inner ears. Through unknown mechanisms, this also affects the hearing portion of the ear and ultimately leads to deafness in both ears in children with NF2. The hearing loss caused by NF2 is a big challenge for children and young adults, as it isolates them from their environment and affects their overall development. The hearing loss is not dependent on the tumor itself, patients with small tumors can be deaf and patients with large tumors can have normal hearing. To this day, we do not know why and when this hearing loss happens in children with NF2, or why it can get worse even if the tumors aren’t growing.

Our new research in mice with NF2 suggests that Schwann cells in the hearing portion of the ear are not functioning properly long before these animals form tumors on the balance nerve. A lack of and abnormal nerve isolation appear to be the underlying reason for worsening hearing loss over time.

To understand the hearing loss in children with NF2 better, we will study inner ears from these animals at different ages to see how the Schwann cell coverings change around the hearing nerve and how they may get affected by a type of immune cell called macrophages.

Overall, this research aims to shed light on why there is hearing loss in patients with NF2 and may help us find new ways to prevent or treat this hearing loss in the future.