title: Approach to the patient with extremely low HDL-cholesterol.
abstract: Patients with extremely low high-density lipoprotein-cholesterol (HDL-C) pose distinct challenges to clinical diagnosis and management. Confirmation of HDL-C levels below 20 mg/dl in the absence of severe hypertriglyceridemia should be followed by evaluation for secondary causes, such as androgen use, malignancy, and primary monogenic disorders, namely, apolipoprotein A-I mutations, Tangier disease, and lecithin-cholesterol acyltransferase deficiency. Global cardiovascular risk assessment is a critical component of comprehensive evaluation, although the association between extremely low HDL-C levels and atherosclerosis remains unclear. Therapeutic interventions address reversible causes of low HDL-C, multiorgan abnormalities that may accompany primary disorders and cardiovascular risk modification when appropriate. Uncommon encounters with patients exhibiting extremely low HDL-C provide an opportunity to directly observe the role of HDL metabolism in atherosclerosis and beyond the vascular system.
authors.affiliation: Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, 11-125 Translational Research Center, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104, USA. rader@mail.med.upenn.edu
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Rader
authors.forename: Emil M
authors.initials: EM
authors.lastname: deGoma
mesh_terms: D016632:Apolipoprotein A-I / Q000172:deficiency; D008076:Cholesterol, HDL / Q000097:blood / Q000172:deficiency*; D003937:Diagnosis, Differential; D006801:Humans; D007863:Lecithin Cholesterol Acyltransferase Deficiency / Q000175:diagnosis / Q000378:metabolism; D008297:Male; D010265:Paraproteinemias / Q000175:diagnosis / Q000378:metabolism; D013631:Tangier Disease / Q000175:diagnosis* / Q000378:metabolism; D055815:Young Adult
chemical_list: D016632:Apolipoprotein A-I; D008076:Cholesterol, HDL