The SBDS mRNA is widely expressed in many tissues and its mutations cause a wide variety of abnormalities and symptoms, so the diagnosis is not always immediately obvious.
The screening for mutations in the SBDS gene started, in our laboratory, in 2003. In a period of 13 years we analyzed, after obtained informed consent, a total of 174 families having one suspected SDS patient. Part of the 174 families were of non-Italian origin: these samples arrived to our laboratory by direct communications from family doctors or by the Genetic Testing Registry (GTR\uae). GTR provides a central location for voluntary submission of genetic test information by providers. As providers of: confirmation of research findings, sequence analysis, genetic counseling, prenatal testing, mutation-specific/carrier testing, we analyzed a total of 28 families from the following nationalities: Australia, Bangladesh, China, Egypt, India, Latvia, Lebanon, Libya, Morocco, Pakistan, Philippines, Romania, Santo Domingo,Turkey, Ukraine, Vietnam.
Among the 25 families, we characterized, as SDS, 8 patients. The median (range)\ua0age at diagnosis\ua0was 2.8 (0.1-7) years.
The clinical status at diagnosis appears very similar between Italian and non-Italian patients. Pancreatic dysfunctions is present in the majority of subjects as well as hematologic abnormalities and infections. The SDS alleles reflect the frequencies observed in Italy. Two mutations are not present in the Italian SDS patients: the missense mutation c.523C>T in exon 4, found in homozygosis and the c.307_308delCA, a frame shift deletion in the exon 3 leading to a premature stop codon.
The SDS is described in even more geographic area of the world among different ethnic population