FUT5 and proximal spinal muscular atrophy: We found more mutations in both SMN1 and other genes, and some of them were associated with the onset of SMA, such as the SMN1 stop-gain mutation c.[271C > T], the SPTA1 insertion mutation c.[−41_-40insCTCT], the FUT5 SNV c.[1001A > G], and the MCCC2 SNV c.[−117A > G].