Spinal muscular atrophy (SMA) is an autosomal recessive disease caused by mutation or deletion of the survival motor neuron gene 1 (SMN1). SMN2, a copy gene, influences the severity of SMA and may be used in somatic gene therapy of patients with SMA in the future. The SMA carrier analysis developed at the Institute of Medical Genetics, Catholic University (Rome), on the Applied Biosystems real-time PCR instruments by Dr Danilo Tiziano and his group, provides a robust workflow to evaluate SMA carrier status. In this study, the SMN2 copy number was confirmed on 22 patients by developing our own assay on the basis of a relative real-time PCR system using the 7500 Fast Real-Time PCR System.