Phenotypical and genotypical expression of Wolfram syndrome in 12 patients from a Sicilian district where this syndrome might not be so infrequent as generally expected.

BACKGROUND: Since the original description, there have been only few epidemiological studies of Wolfram syndrome (WS). AIM: Aims of the present paper are to ascertain WS prevalence and expression in a district of North-eastern Sicily, i.e. a geographic area where consanguineous unions are not very unusual. MATERIALS AND METHODS: Prevalence rates of WS in the Messina district were calculated by taking into consideration both the total population (653,737) and the populations included within the 0-30 year age range (202,681). We estimated the relative prevalence of WS among patients with youth-onset insulin-dependent diabetes mellitus (DM) who are currently aged under 30 years (256). RESULTS: Global WS prevalence in our district is 1:54,478, whereas prevalence among individuals under 30 is 1:16,890 and relative prevalence among patients with juvenile-onset insulin-dependent DM is 1:22.3. When compared with the patients with insulin-dependent DM of Messina district, WS patients did not exhibit significant differences in terms of biochemical features at DM onset, whereas age at DM diagnosis was significantly earlier in WS group. CONCLUSIONS: (a) WS prevalence is not so infrequent as generally expected; (b) in our series, DM presented before 10 years in 11/12 patients and ten cases have already developed all the four peculiar manifestations of WS by 26 years; (c) 9/12 patients exhibited a homozygous frameshift/truncation mutation (Y454_L459del_fsX454), which is the one most frequently found also in patients from other Italian regions; (d) age at DM diagnosis was significantly earlier in WS group than in the patients with insulin-dependent DM of Messina district.