Autonomic Dysregulation in Sitosterolemia: A Unique Case of Recurrent Syncope in a Young Woman

Aisha Shabbir, Jorge L. Reyes, Ciana Keller and David G. Benditt*

Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA

^*Correspondance to: David G Benditt 

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Abstract:

Sitosterolemia is a rare disorder characterized by accumulation of plant-derived sterols within tissues including the nervous system, but not known to cause cardiac autonomic dysfunction. Herein, we report autonomic dysfunction in sitosterolemia leading to recurrent transient loss of consciousness (TLOC). A 25-year-old female with sitosterolemia complained of recurrent chest pain, palpitations, and TLOC on exertion. Testing, including orthostatic vitals and stress echocardiogram were normal, but ambulatory ECG revealed episodic unexplained sinus tachycardia. Given unexplained TLOC, she was referred for autonomic testing which was markedly abnormal with diminished chronotropic response during standing, abnormal Valsalva Phase 2 and absence of Phase 4 overshoot. Both VR (1.3) and RSA (<7 bpm) were low. Symptom reproduction occurred during tilt-table test with nitroglycerin administered to mimic exertion. Given reports of cholesterol crystal brain deposition in sitosterolemia, sterol accumulation may be expected to impair autonomic centers and result in cardiac autonomic dysfunction such as observed here.

Keywords:

Autonomic dysfunction, Tilt table test, Sitosterolemia

Cite the Article:

Shabbir A, Reyes JL, Keller C, Benditt DG. Autonomic Dysregulation in Sitosterolemia: A Unique Case of Recurrent Syncope in a Young Woman. Ann Clin Case Rep. 2025; 10: 2800..