Background We have found a polymorphism in the ECP (eosinophil cationic protein)-gene at position 434 according to GenBank accession number NM 002935. This polymorphism would cause the change of the amino acid arginine (base at position 434 is G) at position 97 to threonine (base at position 434 is C).
Objective To investigate the prevalence of the ECP-polymorphism and to screen for disease associations.
Methods DNA of 209 medical students and 76 asthmatic subjects was analysed. The 434 genotype in the ECP-gene was detected by cleavage of the amplified DNA sequence with the restriction enzyme PstI and analysis of the cleaved product by agarose gel electrophoresis.
Results The prevalences of the polymorphism in the student population were 53%, 39% and 8% for the 434GG, the 434GC and the 434CC genotype, respectively, with allele frequencies of 72% (434G) and 28% (434C). Subjects reporting allergy had a higher prevalence of the 434G allele than non-allergic subjects (P = 0.0056). Of the students who were Phadiatop-positive and had allergic symptoms, 79% had the 434GG genotype, whereas the 434GC and 434CC genotypes were present in 82% of those who did not express allergic symptoms (P < 0.001). Among the 76 patients with asthma, patients with allergic asthma had a significantly higher proportion of 434GG compared with patients with non-allergic asthma (P = 0.04). None of the 18 subjects of the two groups with the 434CC genotype had allergy.
Conclusion The 434(G > C) polymorphism in the ECP-gene is related to the development of allergic symptoms, suggesting a central role for the ECP molecule in the process.