Familial combined hyperlipidemia: current knowledge about pathophysiology, diagnostics and correction

Abstract

The review is devoted to the current knowledge about pathophysiology, diagnostics and correction of familial combined hyperlipidemia (FCHL) that is considered to be the most frequent among primary dyslipidemias in general population (1 — 3 %) as well as among the patients survived after myocardial infarction (20 — 38 %). The current knowledge about genetic characterization of FCHL and its pathophysiology are adduced. FCHL is emphasized to be a heterogenic state and many of genetic determinants are involved in its development. Excessive concentration of apolipoprotein B (ApoB) — containing lipoproteins is shown to be the main biochemical sign of FCHL and hence, the genes of proteins participated in their metabolism could be claimed for genes‑candidates of FCHL. A special attention is paid to the diagnostics of FCHL, the most valuable diagnostic signs of FCHL are emphasized because FCHL is not monogenic disorder and due to its phenotype characterized by high levels of low‑density lipoprotein cholesterol and/or triglyceride (TG), this lipid disorder is not frequently diagnosed. A combination of concentrations of ApoB > 120 mg/dl and TG > 1.5 mmol/l (> 133 mg/dl) with a family history of early cardiovascular debut could be used today for revelation of patients with a probable diagnosis of FCHL. The influence of FCHL on cardiovascular risk (CVR) that is partly realized through its association with metabolic comorbid conditions such as type 2 diabetes mellitus, metabolic syndrome, nonalcoholic fatty liver disease is considered. These comorbid conditions could play a role of etiological causes of cardiovascular disease and could increase a CVR through some common pathophysiological mechanisms such as insulin resistance of muscular and fat tissues and hepatic overproduction of very low‑density lipoproteins. The current approaches to FCHL correction in accordance with acting recommendations are elucidated. They consider its correction to be necessary as a primary atherogenic dyslipidemia and propose to start intervention from the influence on modified factors of CVR (smoking, alcohol consumption, excessive body mass, obesity). Some differential approaches to correction of lipid exchange disorders in FCHL from the beginning of the first line hypolipidemic agent (statin of fibrate) or their combined usage depended on dyslipidemia phenotype revealed during diagnostics of FCHL are discussed. Update combinations of hypolipidemic agents with an addition to statin and fibrate omega‑3 fatty acids, ezetimibe and inhibitors of PCSK9 (alirocumab, evolocumab) from the point of their influence on a reduction of CVR as well as on the components of dyslipidemia phenotype occurred in FCHL are considered.