Increased ratio of incompletely digested gDNA in plasma from SSc patients with DNASE1L3 R206C. (A) Schematic representation of qPCR-based detection of short (Alu 83) and long (Alu 244) fragments of gDNA. (B) Agarose gel showing PCR products after performing PCR with a plasma sample using these primer pairs. (C) Endogenous gDNA abundance as determined using each primer pair with plasma samples from HUVS patients with vs without DNASE1L3 frameshift mutation. Each dot represents one subject. Horizontal lines represent the median for each group. (D) Same as (C), but comparing HC and SSc groups by genotype as indicated. Each dot represents one subject. Red bars in the Alu 83 and Alu 244 figures indicate median and interquartile range. Red bars in the Alu 244/83 figure indicate mean and s.d. ^*P < 0.05, ns: non-significant. (E) Correlation between Alu 244/83 ratio (from Fig. 3D) and plasma DNase activity against AdMV-associated DNA (from Fig. 2D) in SSc patients. AdMV: apoptosis-derived membrane vesicles; gDNA: genomic DNA; HC: healthy control; HUVS: hypocomplementaemic urticarial vasculitis syndrome; qPCR: quantitative PCR