In this study, we showed that DBS on Guthrie cards can be used for the detection of both the homozygous and heterozygous deletion of SMN1. We had already shown that FTA cards, which are designed for the collection and storage of DNA in blood, are useful for the analysis of SMN genes, but we had not shown the applicability of Guthrie cards for the DNA analysis and diagnosis of genetic disorders. This evidence concerns the gene SMN2 and hereditary disease.