The loss of hearing of people suffering from Usher Syndrome type 2A appears not to remain stable, as was always thought. The average deterioration is 5 dB per 10 years, but there are major differences.
In the doctoral research of Bas Hartel, 110 Dutch and Swedish patients with two mutations on the USH 2A gene are involved. This is globally the largest study group of Usher patients.

Bas Hartel found in his doctoral research that the level of progression of loss of hearing with people with the USH 2A gene is related to the different combinations of mutations in this gene.
This study demonstrated that there is a difference between having two serious faults in the USH 2A gene, two mild faults or a combination of a mild and a serious fault. With patients having two serious faults the loss of hearing appears to be faster and stronger than with people in the other two groups.

The entire scientific article can be read by clicking the button.