MAP3K4 and myotonic dystrophy type 1: Using values from INSR, MBNL2, MBNL1, CLASP1, and MAP3K4 and principal component analysis, we created a ddPCR-based composite splicing biomarker score for each specimen, demonstrating a wide separation between the symptomatic DM1 and UA groups, and an intermediate position of the asymptomatic group (Fig. 9b and Supplementary Table 7).