Mondini dysplasia

Mondini Dysplasia, (also known as Mondini malformation and Mondini defect) is an abnormality in the inner ear that can be the cause of hearing loss.

A person with Mondini dysplasia has a cochlea that is incomplete. A normal cochlea has two and a half turns, a cochlea with Mondina dysplasia has two, one and a half, one, or no turns (or increments, obviously). This results in gradual or even sudden hearing loss that may be profound.