Not only patients with DMD/BMD or ME and normal children, as shown in Table 4, but also 20 pairs of the parents of SMA patients (data not shown), who had no symptom, were found to have heterozygous mutations of SMN1, NAIP and GTF2H2. Some of them had no clinical symptom and some of them had clinical symptoms not related to mutations of SMN1, NAIP and GTF2H2. There was no clinical significance for heterozygous mutations of SMN1, NAIP and GTF2H2. Here, NAIP is linked to proximal spinal muscular atrophy.