Acute Coronary Syndrome Developed in a 17-year-old Boy with Sitosterolemia Comorbid with Takayasu Arteritis: A Rare Case Report and Review of the Literature

Abstract

A 17-year-old boy with acute coronary syndrome was admitted to our hospital. He had xanthomas over his elbow and Achilles tendon and a high level of low-density lipoprotein cholesterol; therefore, his initial diagnosis was familial hypercholesterolemia. However, a genetic analysis revealed a compound heterozygous mutation in the ABCG5 gene with a high serum level of sitosterol, leading to the diagnosis of sitosterolemia. After lipid-lowering treatment, percutaneous coronary intervention was performed. Furthermore, a persistently high C-reactive protein level and images of large arteries led to a diagnosis of Takayasu arteritis. To our knowledge, this is the first case of sitosterolemia complicated by Takayasu arteritis.

Keywords: ABCG5; C-reactive protein; heterozygous mutation; low-density lipoprotein cholesterol.

Figure 1.

Xanthomas over the elbows and Achilles tendons before and three months after treatment and a radiograph of the ankle. Xanthomas over the elbows before (A) and after (F) treatment. Xanthomas over the Achilles tendons before (B, C) and after treatment (G, H). Radiography of the ankle shows Achilles tendon thickening (D, right side; E, left side).

Figure 2.

Coronary angiography. The left panel shows 75% stenosis in the left descending artery (LAD) (A), 75% stenosis in the left circumflex artery (LCX) (B), and 99% stenosis in the right coronary artery (RCA) (C, D) on initial coronary angiography. Arrows indicate the stenosis sites. The right panel shows slight regressions in LAD (E) and LCX (F) and the absence of restenosis in the RCA (G, H).

Figure 3.

Findings of optical coherence tomography (OCT) in the right coronary artery. Left panel: The sites (A-F) assessed with OCT in the right coronary artery on coronary angiography. Right panel: OCT images at each site. Yellow arrowheads denote the accumulation of macrophages (high density), white arrowheads denote healed plaque (layered pattern), the white arrow denotes the cavity of the ruptured plaque, and the arced arrow denotes lipid plaque (low density).

Figure 4.

Images that illustrate the findings of Takayasu arteritis. Wall thickening is found in the aortic arch on contrast-enhanced computed tomography (A) and in carotid arteries on magnetic resonance imaging (B). Fluorodeoxyglucose positron emission tomography (FDG-PET) revealing the faint accumulation in the vascular wall of the aortic arch and bilateral common carotid arteries, subclavian arteries, and brachial arteries (C). Arrowheads indicate wall thickening (A, B) and accumulation on FDG-PET (C).

Figure 5.

Smear of peripheral blood. The red arrow indicates a macrothrombocyte, which is larger than erythrocytes.

Figure 6.

Clinical course of the patient. PCI: percutaneous coronary intervention, GS/CS: gastroscopy/colonoscopy