A sudden onset and the spontaneous remission of severe hypo-high-density lipoprotein cholesterolemia without serious underlying disease: A case report

Severe hypo-high-density lipoprotein (HDL) cholesterolemia is defined by serum values less than 20mg/dl. Few acquired cases, without serious underlying disease, have been reported. An asymptomatic 75-y-old man was admitted for evaluation of low serum HDL-cholesterol (HDL-C) levels (2–8mg/dl). The record of periodic medical examinations revealed that a sudden decrease had occurred 5y ago. Mild anemia and proteinuria were noted but the liver and thyroid function tests were normal. β-Quantification revealed a relatively low HDL-C (10.8mg/dl) and the serum lecithin cholesterol acyltransferase (LCAT) activity was low (29.4nmol/ml/h). Unexpectedly, serum HDL-C levels recovered 2y after hospital discharge. In addition, the serum LCAT activity, hemoglobin concentrations, and urine protein tests all returned to within the reference interval. Subsequent examinations could not clarify the cause of the sudden onset and spontaneous recovery of the extremely low HDL-C. We describe an unusual case of acquired HDL-C deficiency in a 75-y-old man that did not have serious pre-existing disease. Recently, extremely low HDL-C levels in patients with the nephrotic syndrome, associated with acquired LCAT deficiency, have been reported. The present case might illustrate a milder form of this disorder, because the clinical findings show many similarities. •We report an unusual case of acquired HDL-C deficiency in an apparently healthy man.•Serum HDL-C levels were determined for the first time using the β-quantification.•Acquired LCAT deficiency seems to lead to low HDL-C, mild anemia, and proteinuria.•Close examination of renal functions may be needed in patients with similar problems.