Etrurians vs Greeks: May ACE I/D polymorphism still be considered as a marker of susceptibility to SSc?

OBJECTIVE: SSc is characterized by immune dysfunction and microvascular involvement. A different genetic background may determine a different polymorphic allele frequency between different populations, and data from literature reported conflicting results about the role of genetic components in predisposing to the disease. We carried out this study in order to compare the ACE I/D polymorphism genotype distribution and alleles frequency in two different populations from the Mediterranean area. METHODS: Forty-eight Italian and 41 Greek SSc patients compared with 112 Italian and 93 Greek controls, have been studied. The ACE I/D polymorphism has been analysed. RESULTS: The genotype distribution and allele frequency were in Hardy-Weinberg equilibrium for Italian and Greek SSc patients and controls. Among the Italian patients a significantly higher ACE D allele frequency than in the controls was found, whereas among the Greeks a higher prevalence was observed in the healthy subjects. A significant difference in ACE D allele frequency between Italian and Greek controls was observed (p = 0.04). ACE D allele was associated to the predisposition to SSc in Italians, but not in Greeks. CONCLUSION: We confirm that Italian SSc patients have a higher ACE D allele frequency that is not present in the Greek patients. Thus, the two populations living in different Mediterranean areas and resulting from the Mediterranean civilization, do not show the same ACE-gene related allele frequencies. Other populations of the Mediterranean area must be investigated by using unlinked genetic markers to verify the homogeneity of the genetic background, and to test for a "true" difference in their ethnic origin.