Incidence of Shwachman–Diamond syndrome

To the Editor: Shwachman-Diamond syndrome (SDS) (OMIM 260400) is a rare autosomal recessive disease first reported in 1964 [1,2].Diagnostic criteria have been updated [3] to cope with a highly variable phenotype including abnormalities in exocrine pancreas, bones and bone marrow [4-6], an increased risk for myelodisplastic syndrome and leukemia and almost specific bone marrow chromosome abnormalities [7].Data concerning the incidence of the disorder, all obtained before the identification of the SBDS gene [8], are scanty and outdated.Kent et al. [9] reported an incidence of 1/200,000; in 1995 a slightly higher estimate, 1/150,000, was suggested by Lozada-Munoz and Del Pilar Aliaga, as cited by Cipolli [10].Goobie et al. [11] estimated the incidence of SDS as 1/76,563.It is relevant to use international registries to obtain similar estimates for all countries, in order to evaluate whether geographical variation in incidence is present and to have better estimates of carrier frequencies for each country to be used for association studies.