In vivo gene transfer of human VPS33B. (A) Schematic of ssAAV2/8 vectors containing wild-type (hVPS33B) and codon optimised (hVPS33Bco) human VPS33B cDNA. (B) Plasma alkaline phosphatase activity levels (p = 0.0016, Kruskal-Wallis test), (C) total plasma bile acid levels (p = 0.0015, Kruskal-Wallis test) (D) Plasma cholesterol levels (p = 0.0023, Kruskal-Wallis test) (E) plasma phospholipid levels (p = 0.0047, Kruskal-Wallis test) and (F) CEA protein localisation assessed 9 weeks after injection of ssAAV2/8-EFS-hVPS33B-WPRE and ssAAV2/8-EFS-hVPS33Bco-WPRE (1 × 1012 vg/mouse) in 5-week-old Vps33bfl/fl-AlfpCre mice (n = 4–6). All mice were fed cholic acid supplemented diet and sacrificed at 14 weeks of age. Graphs are presented with medians and IQR.