Rare LPL gene gene variants common in hypertriglyceridemia
MedWire News: Rare variants in the lipoprotein lipase (LPL) gene are highly prevalent in people with hypertriglyceridemia but uncommon in Type III hyperlipidemia, a German team has found.
David Evans (Universitätsklinikum Hamburg-Eppendorf) and team studied the frequency of rare LPL mutations in people with various forms of hypertriglyceridemia.
"Genome-wide association studies have shown that LPL mutations are associated with plasma triglyceride levels but that common variants account for only 1.25% of the variance," explain Evans and co-authors in the journal Atherosclerosis.
To investigate further, the team analyzed the DNA sequence of the exons and exon/intron boundaries of LPL for 434 individuals.
Of these, 107 had severe hypertriglyceridemia (triglycerides >875 mg/dl [10 mmol/l]); 206 had moderate hypertriglyceridemia (triglycerides >95th percentile for age and gender but <875 mg/dl); 109 had Type III hyperlipidemia (apolipoprotein B/total cholesterol ratio >0.15); and 12 had the APOE2/2 genotype.
Genotyping identified 27 LPL variants, just seven of which were previously known single-nucleotide polymorphisms. The 20 newly identified variants were all present as heterozygotes, 16 were missense mutations (all but one of which resulted in an amino-acid change), two were short deletion mutations, one was a single nonsense mutation, and one was an insertion mutation.
The prevalence of at least one rare LPL variant was 12.1% among patients with severe hypertriglyceridemia and 4.9% in those with moderate hypertriglyceridemia, but just 1.8% among those with Type III hyperlipidemia.
Evans and co-authors conclude: "We confirm the importance of rare variants in the LPL gene in severe hypertriglyceridemia and show that such rare variants are also frequent in patients with moderate hypertriglyceridemia but do not play a role in the development of Type III hyperlipidemia."
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By Joanna Lyford