SUN-LB011 Sitosterolemia: An Interesting Case of Normocholesterolemic Xanthomas

INTRODUCTION Sitosterolemia is an inherited disorder of sterol metabolism in which an excess of many plant sterols, including sitosterol and campesterol, is absorbed and not enough is excreted. Patient with this condition develop tendon xanthomas early in life and are at risk for premature atherosclerosis similar to patients with familial hypercholesterolemia. However, patients with sitosterolemia have normal to mildly elevated plasma cholesterol. We present a patient diagnosed with sitosterolemia using a plant sterol assay and treated with dietary restriction and ezetimibe, a sterol absorption inhibitor. CLINICAL CASE A 45-year-old female was evaluated by a cardiologist for painful Achilles tendon xanthomas which she had since age 9. Family history was pertinent for hyperlipidemia in father and grandparents but their lipid profiles were unavailable. Paternal grandmother died of MI at age 55. She was a non-smoker and without hypertension nor diabetes. Initial lipid profile showed total cholesterol = 179 mg/dl (normal = 0-200); triglycerides = 35 mg/dl (normal = 0-150); HDL cholesterol = 70 (normal =40-60); LDL= 102 (normal=0-100). She was referred to our endocrine clinic. Physical exam was pertinent for bilateral Achilles tendon xanthomas. The diagnosis of sitosterolemia was considered. Plant sterol assay was ordered and showed high sitosterol level at 13 ug/ml (normal=0-5) and campesterol level at 23 ug/ml (normal =0-7). Dietary restriction of plant sterols was advised in addition to initiation of ezetimibe. On subsequent follow-up visits, lipid profile showed total cholesterol = 190 mg/dl; triglycerides = 73 mg/dl; HDL cholesterol = 79; LDL= 96. Plant sterol assay normalized with sitosterol level at 2.1 ug/ml (normal=0-5) and campesterol level at 3.8 ug/ml (normal =0-7). She saw a podiatrist and received radiofrequency and mesenchymal stem cell therapy for her painful tendon xanthomas. Her pain improved. Lipid profile and plant sterol assays are still within normal. Screening stress echocardiogram was normal. CONCLUSION The diagnosis of sitosterolemia should be considered in patients presenting with normocholesterolemic xanthomas. Plant sterol assays are necessary in screening for this condition. Early diagnosis leads to correct treatment and better prognosis. REFERENCE Tzavella, E et al. (2017) Sitosterolemia. J Clin Lipidol, 4, 1095-1100 Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.