Sitosterolemia Exhibiting Severe Hypercholesterolemia with Tendon Xanthomas Due to Compound Heterozygous ABCG5 Gene Mutations Treated with Ezetimibe and Alirocumab

Intern Med. 2020 Dec 1;59(23):3033-3037. doi: 10.2169/internalmedicine.3811-19. Epub 2020 Jul 21.

Abstract

We herein report a rare case presenting with severe hypercholesterolemia, massive Achilles tendon xanthomas, and multi-vessel coronary artery disease. Initially, the patient was misdiagnosed with familial hypercholesterolemia. However, a genetic analysis using our custom sequencing panel covering genes associated with Mendelian lipid disorders revealed him to have a genetic basis of sitosterolemia with compound heterozygous mutations in the adenosine triphosphate binding cassette subfamily G5 (ABCG5) gene. A comprehensive genetic analysis can be particularly useful for diagnosing cases with severe phenotypes, leading to appropriate and medical therapies. Our patient was refractory to statins, whereas ezetimibe and PCSK9 inhibitor with a low-plant-sterol diet successfully reduced his serum levels of low-density lipoprotein cholesterol.

Keywords: ABCG5; PCSK9 inhibitor; sitosterolemia.

Publication types

  • Case Reports

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily G, Member 5 / genetics*
  • Achilles Tendon / physiopathology
  • Antibodies, Monoclonal, Humanized / therapeutic use*
  • Anticholesteremic Agents / therapeutic use
  • Cholesterol, LDL / blood
  • Cholesterol, LDL / drug effects
  • Ezetimibe / therapeutic use*
  • Humans
  • Hypercholesterolemia / complications
  • Hypercholesterolemia / diagnosis
  • Hypercholesterolemia / drug therapy*
  • Hypercholesterolemia / etiology
  • Hypercholesterolemia / genetics
  • Intestinal Diseases / complications
  • Intestinal Diseases / diagnosis
  • Intestinal Diseases / drug therapy*
  • Intestinal Diseases / genetics*
  • Lipid Metabolism, Inborn Errors / complications
  • Lipid Metabolism, Inborn Errors / diagnosis
  • Lipid Metabolism, Inborn Errors / drug therapy*
  • Lipid Metabolism, Inborn Errors / genetics*
  • Male
  • Middle Aged
  • Mutation
  • Phytosterols / adverse effects*
  • Phytosterols / genetics
  • Treatment Outcome
  • Xanthomatosis / drug therapy*
  • Xanthomatosis / etiology
  • Xanthomatosis / physiopathology

Substances

  • ATP Binding Cassette Transporter, Subfamily G, Member 5
  • Antibodies, Monoclonal, Humanized
  • Anticholesteremic Agents
  • Cholesterol, LDL
  • Phytosterols
  • Ezetimibe

Supplementary concepts

  • Sitosterolemia