Usher Syndrome Type 2A: A Review of the Disease and its Correlation with Age and Functional Parameters

Usher syndrome type 2A (USH2A) is a genetic disease characterized by bilateral neuro-sensory hypoacusia and retinitis pigmentosa (RP). The disease is caused by mutations in the USH2A gene, which codes for the protein harmonin. This protein plays a crucial role in the development and maintenance of the inner ear and retina.

The severity of RP in USH2A patients can vary greatly, with some individuals experiencing mild vision loss while others may have more severe visual impairment. A recent study published in found that the cumulative staging score (CS) was positively correlated with age, indicating that older patients tend to have worse visual acuity.

In addition to age, other functional and morphological parameters can also be used to stage RP in USH2A patients. These include measures of retinal function such as electroretinogram (ERG) and optical coherence tomography (OCT). ERG is a non-invasive test that measures the electrical activity of the retina, while OCT uses light waves to image the retina and measure its thickness.

The study found that CS was also negatively correlated with log10 ERG amplitudes, indicating that patients with lower ERG amplitudes tend to have worse visual acuity. This suggests that ERG may be a useful tool for assessing retinal function in USH2A patients.

Furthermore, the study found that SRI (sub-RPE illumination) was positively correlated with CS, indicating that patients with higher SRI values tend to have better visual acuity. This is consistent with previous studies that have shown that SRI can be used as a marker of retinal health in USH2A patients.

In conclusion, the study found that RP severity score in USH2A patients was correlated with age and additional functional and morphological parameters not included in the international staging system. The results suggest that CS may be a useful tool for assessing RP severity in USH2A patients and that ERG and OCT can provide valuable information about retinal function and structure.

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Usher syndrome type 2a