Survival Motor Neuron 1 (Smn1) Gene Acts As A Promising Prognostic Biomarker For Potential Spinal Muscular Atrophy In The Chinese Population

Spinal muscular atrophy (SMA) is a group of neuromuscular disorders characterized by degeneration of the anterior horn cells of the spinal cord. This study aimed to investigate the prognostic role of the SMN1 gene in the pathogenesis of SMA. A total of 1648 peripheral blood samples were obtained from volunteers at The Third Affiliated Hospital of Guangzhou Medical University. Genotype of SMA patients and SMN1 deletion status of 252 SMA patients' parents were investigated using multiplex ligation-dependent probe amplification (MLPA). Universal primer multiplex PCR was used to simultaneously amplify fragments of the SMN1, beta-globin, and KRIT1 genes. We used logistic regression to compare SMA risk and calculated odds ratios with 95% confidence intervals. Results indicated that there were 457 SMA patients with homozygous SMN1 deletions (94.8% of patients examined), and 25 SMA patients with heterozygous SMN1 deletions (5.2% of patients examined). SMN1-1 in both father and mother accounted for 95.6% (241 cases), and SMN1 gene on 1 allele (SMN1-1) or SMN1 gene on 2 alleles (SMN1-2) in either father or mother accounted for 4.4% (11 cases). Among the 217 participants, there were 101 individuals carrying the SMN1-1 copy (accounting for 46.5%) and only 9 individuals carrying SMN1-2 copy (accounting for 2.1%). The inheritance risk of SMA is 25% when both parents are SMN1-1 carriers. The risk ratio of SMA is 5.2x10(-3) when only the father or mother is an SMN1-1 carrier. In conclusion, the SMN1 gene acts as a prognostic biomarker for SMA, and provides information for genetic counseling and aristogenesis fine rearing.