SMN2 and proximal spinal muscular atrophy: Causes an amino acid change from Ala to Gly at position 2, this variant has previously been described as disease causing for Spinal muscular atrophy (38), G-711A was found to be most significant with identification in SMA type II = 3 copies of SMN2, T-1040A was found to be most significant with identification in SMA type I = 2 copies of SMN2, and T-1058A was found in SMA patients as (Type I = 2 copies of SMN2 and Type II = 3 copies of SMN2).