Analysis of the spectrum of identified variants in the USH2A gene in 55 patients with the isolated RP form showed that the most common pathogenic variants were the previously described c.13335_13347delinsCTTG (p.(Glu4445_Ser4449delinsAspLeu)) and c.11864G>A (p.(Trp3955*)), identified in 23 and 17 chromosomes with mutations, respectively (variant frequencies of 20.9% and 15.5%) (Table 2). Here, USH2A is linked to retinitis pigmentosa 1.