Figure 1

Average relative quantities for SMN1. (a) First-pass average relative quantities (RQs). Includes data from all subjects with an initial valid spinal muscular atrophy (SMA) screen falling into screen negative (RQ ≥0.8; N = 3,620; circles), heterozygous deletion (RQ = 0.300–0.599; N = 52; triangles), or homozygous deletion (RQ = 0; N = 1; square) RQ ranges. Excludes screens that initially failed QC metrics (RNAseP Ct ≥35.0 or CV ≥0.200; N = 120) or had average RQs in the equivocal range (0.600–0.799; N = 33). (b) Average RQs obtained from all samples requiring retesting. Average RQs for the initial (filled) and duplicate repeat tests (open) shown for each of 206 subjects requiring a repeat due to QC failure (N = 120; 3.1%), for those with an initial RQ in the equivocal range (0.600–0.799; N = 33; 0.9%), or for confirmation of heterozygous (N = 52; 1.4%) or homozygous deletions (N = 1; 0.03%). All but one sample (variant of uncertain significance carrier) initially in the equivocal range resolved as screen negative (N = 30) or carriers (N = 2) upon retesting. Results are shown according to final outcome (screen negative, circles; carriers, triangles; SMA, square; rare variant carrier, diamond). Initial replicates failing QC or falling in the equivocal range are included. CV, assay failure due to high coefficient of variation (CV ≥0.200); CV/RP, high CV or RNAseP fail; EQ, average RQ falling in equivocal range (0.600–0.799); Het Del, heterozygous deletion; RP, assay replicate fail due to RNAseP Ct ≥35; RQ, relative quantity, SMA, spinal muscular atrophy. A full color version of this figure is available at the Genetics in Medicine journal online.