PLS3 and proximal spinal muscular atrophy: Given that PLS3 has been associated with a protective role in female SMA patients, we also performed a restricted comparison of PLS3 mRNA and protein values in fibroblast and MN samples from the unaffected M-26 carrier mother, the SMA type III S3-63 and S4-34 and the type IV S1-28 daughters, excluding the male samples.