SMN1 and proximal spinal muscular atrophy: A challenge in screening for SMA in Qatar was highlighted after the identification of newborns with SMA born to couples in which one parent was an SMA “silent carrier” with two copies of the SMN1 gene (OMIM 600354) on one chromosome 5 and a second chromosome 5 with zero copies (also known as “2 + 0” genotype).