The specific objects of this study included the analysis of (i) the structural features by similarity search and molecular modeling, (ii) the frequency of sensitization to the apple GRP in a random population of suspected allergics, (iii) the frequency of sensitization in a subpopulation of the patients sensitized to GRP, (iv) reported allergy symptoms of patients following the apple ingestion and (v) a comparative analysis of the structural and immunological features of apple GRP with homologous allergenic proteins. This evidence concerns the gene GRP and allergic disease.