Fruit fly models with CPD mutations exhibited ear-related behavioral changes, reinforcing the link between CPD dysfunction and hearing loss.

Additional fruit fly studies support CPD-like gene involvement in inner ear damage, strengthening the proposed mechanism.

A University of Chicago-led study identifies CPD (carboxypeptidase D) mutations as a cause of rare congenital sensorineural hearing loss and highlights potential treatments.

The findings point to CPD’s role in maintaining arginine levels and rapid signaling in hair cells, suggesting that restoring this pathway could be a viable treatment for those affected.

Researchers identified three CPD gene mutations linked to rare congenital sensorineural hearing loss in three Turkish families, with early-onset implications.

Extended analysis across Turkish families and additional data ties CPD mutations to reduced arginine production and disruptions in nitric oxide signaling within the cochlea.

Researchers caution that results from cell and animal models are preliminary and plan larger human studies while pursuing gene therapy avenues.

The study identifies a therapeutic target and notes the potential to repurpose FDA-approved drugs to treat this form of rare hearing loss, with findings published in the Journal of Clinical Investigation.

CPD mutations reduce arginine, suppressing downstream signaling like cGMP and nitric oxide, which stresses and damages hair cells essential for hearing in both mouse and human tissues.

Disrupted CPD-driven arginine production leads to diminished nitric oxide and cGMP signaling, contributing to hair cell vulnerability and hearing loss.

Therapeutic tests, including arginine supplementation and sildenafil (Viagra), improved hair cell survival and mitigated hearing-related behavioral deficits in models.

Sildenafil showed promise by enhancing cGMP signaling, offering another potential treatment pathway for this genetic deafness.

Experiments in human skin and mouse cochleas show that adding arginine reduces cell death and restores signaling molecules, pointing to L-arginine as a potential therapy.