The most severe forms of spinal muscular atrophy (SMA) are considered to be a leading genetic cause of infant mortality. As a result, SMA is a very important disorder for carrier screening research studies. SMN1 and SMN2 are very similar in sequence: the functional difference between the two is a single nucleotide change—from a cytosine to a thymine in exon 7. This homology presents special challenges for NGS technologies commonly used in expanded carrier screening research. In this eCase study, Dr.