Figure 1.

The four genetically SI-characterized (chromosome 3-NC_000003.12) subjects undertook ¹³C-S/GBT with simultaneous breath and blood sampling for plasma fermentation to release ¹³CO₂ to validate breath sample enrichment outcomes; Phase I ¹³C-sucrose oxidation data and plasma fermentation data are shown. (a) 45.9 y/o healthy, asymptomatic woman without suspected SI gene mutation and normal CGO for ¹³C-sucrose (>80%); (Chr. 3q25.2-26.2) WT/WT. (b) 23.3 y/o symptomatic woman with heterozygous SI gene mutation and abnormal mean CGO for ¹³C-sucrose (<80%); Chr. 3q25.2-26.2 [c.3218G>A (p.G1073D)/WT]. (c) 53.9 y/o symptomatic woman with heterozygous SI gene mutation and abnormal mean CGO for ¹³C-sucrose (<80%); Chr. 3q25.2-26.2 [c.5234T>G (p.P1745C)/WT]. (d) 46.7-year-old symptomatic woman with homozygous SI gene mutation and abnormal (very low) mean CGO for ¹³C-sucrose (c/o < 80%); Chr. 3q25.2-26.2 [c.3218G>A (p.G1073D)/c.3218G>A (p.G1073D)]. B: ¹³CO₂ breath sample enrichment (delta per mil); P: plasma sample ¹³CO₂ enrichment (delta per mil); C: theoretical target ¹³CO₂ plasma enrichment derived from in vitro reference substrate (¹³C-glucose 3 mg/L).