Retinitis pigmentosa (RP) is a group of inherited diseases that damage rod and cone cells located in human retina. A nonsense mutation R677X has been identified in RP1 gene which not only causes mRNA degradation but also results in truncated protein production leading towards visual disparity in humans. Secondary structure of RP1 gene was determined in order to elucidate the structural changes conferred due to nonsense mutation R677X. The structural differences among non mutated and mutated RP1 gene range from 23% to 43%. Similarly the truncated protein also resulted in the loss of certain functional as well as active sites which were identified by predicting motifs. A detailed comparison between non mutated and mutated RP1 gene revealed the significance of R677X mutation causing significant structural (helix, sheet and coil) as well as functional loss. This is useful for future work for annotating the functions of protein using their structures.