RHO Variants and Autosomal Dominant Retinitis Pigmentosa: Insights from the Italian Genetic Landscape

Autosomal dominant retinitis pigmentosa (AD-RP) is caused by several genes, among which RHO is one of the most investigated. This article will be focused on RHO and its role in explaining AD-RP cases in the Italian population, taking advantage of the experience of the Genomic Medicine Laboratory UILDM at the Santa Lucia Foundation IRCCS. The retrospective evaluation of the distribution of RHO variants in the Italian patients with a clinical suspicion of RP pointed out eight variants. Of them, four variants (c.632A>T, c.1040C>T, c.1030C>T, c.383_392del) were pathogenic and made it possible to confirm the diagnosis of AD-RP in nine affected patients, highlighting a lower frequency (17%) of RHO variants compared to previous studies (30-40%). In addition, this study identified four variants classified as Variants of Uncertain Significance (VUS). In conclusion, the experience of the Genomic Medicine Laboratory provides an overview of the distribution of RHO variants in the Italian population, highlighting a slightly lower frequency of these variants in our cases series compared to previous reports. However, further studies on RHO variants are essential to characterize peculiar RP phenotypes and extend the spectrum of disease associated with this gene.