Total RNA was extracted using TRIzol Reagent (Invitrogen). RT-PCR was performed using SuperScript III One-Step RT-PCR System with Platinum Taq High Fidelity (Invitrogen). The primers were designed to detect only SMN2 sequences (not to detect SMN1) in the SMA cell line, as the fibroblast cells from this patient have a deletion mutation of exons 7 and 8 in SMN1. The SMN2 primer sequences were 5′-CTGCCTCCATTTCCTTCTG-3′ (Forward) in exon 6 and 5′-TGGTGTCATTTAGTGCTGCTC-3′ (Reverse) in exon 8. The GAPDH primer sequences were 5′-TCCCTGAGCTGAACGGGAAG-3′ (Forward) and 5′-GGAGGAGTTTGGTCGCTGT-3′ (Reverse). The cDNA was synthesized for 5 min at 50 °C. The SMN2 exon 6–8 was amplified with 30 PCR cycles (94 °C for 15 sec, 60 °C for 30 sec, 68 °C for 25 sec). The GAPDH was amplified with 20 PCR cycles (94 °C for 15 sec, 60 °C for 30 sec, 68 °C for 20 sec).