SMN1 and proximal spinal muscular atrophy: After the SMN protein forms a complex with the hnRNPs and the RGG box, the complex interacts with pre-mRNA and nuclear mRNA and plays an important role in the processing and transport of mRNA.7Owing to the faulty production of the SMN protein, snRNPs cannot interact with other molecules and the functions of motor axons are negatively affected because of splicing errors.8The faulty production of the SMN protein leads to defective functions of both molecular biological features and metabolic activities.9The clinical severity of SMA disease may differ among patients.