Abstract
Hypolipidemia (hypocholesterolemia, hypotriglyceridemia) is a biochemical symptom characterized by a decrease in LDL-cholesterol (<= 1.30 mmol/L) and/or triglycerides (<= 0.50 mmol/L), which is not caused by specific hypolipidemic treatment. The causes of the primary, resp. familial hypobetalipoproteinemia (HBL) are mutations in the MTTP, APOB and PCSK9 genes.
Severe forms of familial hypocholesterolemias occur in three diseases with a similar clinical picture (homozygous familial hypobetalipoproteinemia, abetalipoproteinemia, chylomicron retention disease). Familial combined hypolipidemia (FCHL) is caused by a mutation (with a loss of function) in the ANGPTL3/4 gene.
Pure familial hypotriglyceridemia has been reported in familial apoCIII deficiency. In contrast, secondary, acquired hypocholesterolemia and hypotriglyceridemia are more common and occur in a number of diseases - critical physical illness, acute and chronic hepatic parenchymal disease, severe malnutrition, malassimilation syndromes, thyrotoxicosis, end stage renal disease, solid tumors and hematological malignancies.
Hypolipidemia is also accompanied by acute and chronic infections as well as neuropsychiatric diseases (such as depression, and suicidal tendency). Hypolipidemia is an important symptom because it can be a manifestation of as yet undiagnosed serious disease (i), in critical illness and chronic liver disease hypolipidemia correlates with the prognosis of disease (ii); hypocholesterolemia increases the risk of some diseases (intracerebral hemorrhage, DM2T, osteoporotic fractures in DM, suicide, depressive disorders) (iii).