title: PCSK9 R46L, lower LDL, and cardiovascular disease risk in familial hypercholesterolemia: a cross-sectional cohort study.
abstract: OBJECTIVE
  Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a downregulator of the low density lipoprotein receptor. The aims of this cross-sectional cohort-study were to examine whether the PCSK9 R46L loss of function variant found in a cohort of familial hypercholesterolemia (FH) patients was associated with lower low density lipoprotein cholesterol, lower frequency of xanthomata, and cardiovascular risk.
  
  
  RESULTS
  We studied FH patients attending the IRCM (Institut de Recherches Cliniques de Montréal) Lipid Clinic and whose DNA genotyping was positive for a low density lipoprotein receptor mutation. The presence of the PCSK9 loss of function R46L missense variant was determined among a cohort of 582 FH patients by genotyping. Frequency of the R46L variant was 3%. Carriers had significantly lower low density lipoprotein cholesterol (11%, P=0.002), total cholesterol (9%, P=0.007), apolipoprotein B (10%, P=0.037), and non-high density lipoprotein (12%, P<0.001) concentrations compared with noncarriers. Furthermore, R46L carriers showed a decreased average number of xanthoma per individual compared with noncarriers (0.33 and 0.76, respectively; P<0.001). Importantly, the R46L genetic variant was associated with a significant 86% lower odd of presenting a cardiovascular event (odds ratio, 0.14; 95% confidence interval, 0.032-0.63; P=0.001).
  
  
  CONCLUSIONS
  Even though the R46L variant was present in 3% of our FH population, carriers of this polymorphism showed attenuated effect of the low density lipoprotein receptor mutation on parameters, such as low density lipoprotein cholesterol, apolipoprotein B, total cholesterol, and non-high density lipoprotein. More importantly, this mutation is associated with a significant lower risk of cardiovascular disease compared with noncarriers. It is therefore likely that targeting PCSK9 in FH patients with novel anti-PCSK9 therapies will be useful in reducing cardiovascular risk in affected subjects.
authors.affiliation: From the Department of Medicine, Division of Experimental Medicine, Institut de Recherches Cliniques de Montréal (IRCM), Nutrition, Metabolism and Atherosclerosis Clinic, Montréal, Canada (Y.G.L.S., A.B.); Medicine Department, McGill University, Montréal, Canada (Y.G.L.S., R.D., J.D., A.B.); and Nutrition Department, University of Montreal, Montréal, Canada (R.D., J.D.).
authors.forename: Yascara Grisel Luna
authors.initials: YG
authors.lastname: Saavedra
authors.affiliation: From the Department of Medicine, Division of Experimental Medicine, Institut de Recherches Cliniques de Montréal (IRCM), Nutrition, Metabolism and Atherosclerosis Clinic, Montréal, Canada (Y.G.L.S., A.B.); Medicine Department, McGill University, Montréal, Canada (Y.G.L.S., R.D., J.D., A.B.); and Nutrition Department, University of Montreal, Montréal, Canada (R.D., J.D.).
authors.forename: Robert
authors.initials: R
authors.lastname: Dufour
authors.affiliation: From the Department of Medicine, Division of Experimental Medicine, Institut de Recherches Cliniques de Montréal (IRCM), Nutrition, Metabolism and Atherosclerosis Clinic, Montréal, Canada (Y.G.L.S., A.B.); Medicine Department, McGill University, Montréal, Canada (Y.G.L.S., R.D., J.D., A.B.); and Nutrition Department, University of Montreal, Montréal, Canada (R.D., J.D.).
authors.forename: Jean
authors.initials: J
authors.lastname: Davignon
authors.affiliation: From the Department of Medicine, Division of Experimental Medicine, Institut de Recherches Cliniques de Montréal (IRCM), Nutrition, Metabolism and Atherosclerosis Clinic, Montréal, Canada (Y.G.L.S., A.B.); Medicine Department, McGill University, Montréal, Canada (Y.G.L.S., R.D., J.D., A.B.); and Nutrition Department, University of Montreal, Montréal, Canada (R.D., J.D.). Alexis.Baass@ircm.qc.ca.
authors.forename: Alexis
authors.initials: A
authors.lastname: Baass
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000097:blood / Q000209:etiology / Q000235:genetics; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology* / Q000235:genetics; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005787:Gene Frequency; D006579:Heterozygote; D006801:Humans; D006938:Hyperlipoproteinemia Type II / Q000097:blood / Q000150:complications* / Q000235:genetics; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D008875:Middle Aged; D050505:Mutant Proteins / Q000097:blood / Q000235:genetics; D020125:Mutation, Missense; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases / Q000097:blood / Q000235:genetics*; D011973:Receptors, LDL / Q000235:genetics; D012307:Risk Factors; D012697:Serine Endopeptidases / Q000097:blood / Q000235:genetics*; D014973:Xanthomatosis / Q000097:blood / Q000209:etiology / Q000235:genetics; D055815:Young Adult
chemical_list: D008077:Lipoproteins, LDL; D050505:Mutant Proteins; D011973:Receptors, LDL; C472125:PCSK9 protein, human; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D012697:Serine Endopeptidases
keywords: FH; LDL-C; PCSK9; cardiovascular; hypercholesterolemia; xanthomas