Carotid intima media thickness in a girl with sitosterolemia carrying a homozygous mutation in the ABCG5 gene.

BACKGROUND: Sitosterolemia is a rare lipid metabolism disorder that involves storage of plant sterols. This disease is associated with atherosclerosis, but detailed vascular endothelial assessment is difficult.

CASE PRESENTATION: We report a 5-year-old girl with sitosterolemia who presented with xanthomas at 23 months of age. Her total cholesterol was 868 mg/dL, and her plasma sitosterol level was 9.48 mg/dL. Direct sequencing detected a homozygous mutation in gene ABCG5 (p.Arg389His). Echocardiographic examination revealed that the carotid artery intima media thickness (cIMT) was 0.4 mm with heterogenous hyperechogenicity inside the arterial wall. She was treated using dietary therapy and ezetimibe, which effectively lowered her sitosterol levels. After 3 years of treatment, her cIMT was stable in diameter and arterial wall echogenicity had improved.

CONCLUSIONS: Sitosterolemia is a unique disorder in which it is difficult to avoid premature atherosclerosis because of high sitosterol levels. cIMT measurement with arterial wall assessment may improve management.