Furthermore, the low-frequency E167K variant of TM6SF2 and rare mutations in APOB, which impair very low-density lipoproteins secretion, predispose to progressive fatty liver.
Partial MTP inhibition using small molecule inhibitors, such as lomitapide, can effectively lower plasma low-density lipoprotein-cholesterol and apolipoprotein B levels, but is associated with gastrointestinal side effects and hepatic steatosis, whose long-term sequelae remain unclear; lomitapide has accordingly only been approved as a treatment for homozygous familial hypercholesterolemia.
We used exome sequencing to discover a novel nonsense mutation in exon 26 of APOB (p.K2240X) responsible for low cholesterol and fatty liver in a large kindred.
Familial hypobetalipoproteinaemia (FHBL) is a codominant disorder characterised by fatty liver and reduced plasma levels of low-density lipoprotein (LDL) and its protein constituent apolipoprotein B (apoB).
Moreover, very low-density lipoprotein (VLDL) subclass analysis showed that the VLDL2 fraction of the fatty liver subgroup contained significantly less cholesterol and triglycerides (P = .02 for both parameters), which was likely explained by a decreased VLDL2 particle number because VLDL2 apolipoprotein B levels tended to be lower (P = .08).
We conclude that hepatic steatosis in apoB/BATless mice is associated with elevated rates of hepatic lipogenesis that are linked directly to increased hepatic expression of PPARgamma2.
Fatty liver is frequent in the apolipoprotein B (apoB)-defective genetic form of familial hypobetalipoproteinemia (FHBL), but interindividual variability in liver fat is large.
Familial hypobetalipoproteinemia (FHBL) is a genetically heterogeneous condition characterized by very low apolipoprotein B (apoB) concentrations in plasma and/or low levels of LDL-cholesterol (LDL-C) with a propensity to developing fatty liver.
This study suggests that: i) fatty liver invariably develops in FHBL carriers of short and medium-size truncated apoBs (< apoB-48), but its occurrence needs additional environmental factors in carriers of longer apoB forms; ii) intestinal lipid malabsorption develops only in carriers of short truncated apoBs, which are not secreted into the plasma; and iii) cerebrovascular disease due to premature atherosclerosis may occur even in FHBL subjects.