Usher Syndrome on the Island of Ireland: A Genotype-Phenotype Review

Researchers studied Usher syndrome in Ireland to better understand the phenotypic and genotypic characteristics in this population. 145 individuals were identified from an Irish Inherited Retinal Dystrophy registry. In this cohort, Usher type 2 was the most common, followed by type 1, then type 3, and a single case of type 4. Genetic testing, vision, hearing, and balance tests were measured.  Of those with positive genetic testing results (82.1%), most common genes were USH2A (causes Usher syndrome type 2a) and MYO7A (causes Usher syndrome type 1b). From the vision testing, the researchers found that the retinitis pigmentosa was similar in all types of Usher, differing only by age of onset and rate of progression. 

What this means for Usher syndrome: The similarity  in the retinitis pigmentosa between all types of Usher syndrome in this cohort suggests that there is potential for gene-agnostic therapies that may benefit all types of Usher. Additionally, the distribution of genotypes in this study could be used to inform future clinical trials.

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