Prevalence of Wolfram syndrome is not necessarily so infrequent as generally expected

Background: Wolfram first reported the combination of juvenile-onset diabetes mellitus (DM) and optic atrophy (OA) in 1938. With the discovery of two other essential components, diabetes insipidus (DI) and deafness (D), Wolfram syndrome (WS) is now also known by the acronym DIDMOAD. Prevalence has been estimated as 1:770000 in the UK (with a carrier frequency of 1 in 354). According to the most recent epidemiological study, WS prevalence in North India has been estimated as 1:805000. Objective: Aim of the present study was to evaluate WS prevalence in a mountainous area of North-eastern Sicily, where consanguineous unions are not very unusual. Population and methods: Our study population included 12 Caucasian WS patients from 7 couples and 5 unrelated families of North-eastern Sicily area, aged between 9 and 29 years (mean age 22.1 ± 5.6 years). Prevalence rates of WS in Messina district were calculated by taking into consideration both the total population and the populations included within the 0-30 year age range. We also estimated the relative prevalence of WS among patients with youth-onset insulin-dependent diabetes mellitus who are currently aged under 30 years (256). Results: According to our findings, global WS prevalence in our district is 1:54478, whereas prevalence among individuals under 30 is 1:16890 and relative prevalence among patients with juvenile-onset insulin-dependent diabetes mellitus is 1:22.3. If only the five patients from non-consanguineous unions were considered for epidemiological purposes the frequency in our district would be around 1:130000 (1:40000 within the 0-30 year age range). Conclusions: a) The frequency of WS in the total population of a North-eastern Sicilian district might be estimated as 1 in around 55000 inhabitants, which is distinctly higher if compared with the frequencies reported in both UK and North-India, b) WS is not necessarily so infrequent, as generally expected