Comparative study of third-generation sequencing-based CASMA-trio and STR linkage analysis for identifying SMN1 2 + 0 carriers.

Spinal Muscular Atrophy (SMA, MIM#253300) is an autosomal recessive neuromuscular disorder caused by defects in the Survival Motor Neuron (SMN) gene. The SMN1 gene, recognized as the primary pathogenic gene for SMA, exhibits a high degree of sequence homology with SMN2 gene. Individuals with the SMN1 2 + 0 genotype represent a unique type of SMA carrier, characterized by two SMN1 copies on one chromosome and zero copies on the other.