Earlier analysis of the Italian population showed patterns of genetic
differentiation that were
interpreted as being the result of population settlements going back to
pre-Roman times. DNA
disease mutations may be a powerful tool in further testing this hypothesis
since the analysis of
diseased individuals can detect variants too rare to be resolved in normal
individuals. We present
data on the relative frequencies of 60 cystic fibrosis (CF) mutations in
Italy and the geographical
distribution of the 12 most frequent CF mutations screened in 3492 CF
chromosomes originating in
13 Italian regions. The 12 most frequent mutations characterize about 73%
of the Italian CF
chromosomes. The most common mutation, ΔF508, has an average frequency
of
51%, followed by
N1303K and G542X, both with average frequencies around 5%. Multivariate
analyses show that the
relative frequencies of CF mutations are heterogeneous among Italian regions,
and that this
heterogeneity is weakly correlated with the geographical pattern of non-DNA
‘classical’ genetic
markers. The northern regions are well differentiated from the central-southern
regions and within
the former group the western and eastern regions are remarkably distinct.
Moreover, Sardinia shows
the presence of mutation T338I, which seems absent in any other European
CF chromosome. The
north-western regions of Italy, characterized by the mutation 1717-1G→A,
were
under Celtic influence, while the north-east regions, characterized by
the
mutations R1162X, 2183AA→G and
7115G→A, were under the influence of the Venetic culture.