Genetic variants in triglyceride metabolism genes among individuals with hypertriglyceridemia in Colombia

BACKGROUND: The genetic substrate of severe hypertriglyceridemia (sHTG) in Latin America is insufficiently understood. OBJECTIVE: To identify genetic variants in genes related to triglyceride (TG) metabolism among adults with sHTG from Colombia. METHODS: In individuals with plasma TG≥880 mg/dL at least once in their lifetime, we amplified and sequenced all exons and intron/exon boundaries of the genes LPL, APOC2, APOA5, GPIHBP1 and LMF1. For each variant we ascertained its location, zygosity, allelic frequency and pathogenicity classification according to American College of Medical Genetics (ACMG) criteria. RESULTS: The study included 166 participants (62 % male, mean age 50), peak TG levels ranged between 894 and 11,000 mg/dL. We identified 92 variants: 19 in LPL, 7 in APOC2, 11 in GPIHBP1, 38 in LMF1, and 17 in APOA5. Eighteen of these variants had not been reported. We identified a new pathogenic variant in LMF1 (c.41C>A; p.Ser14*), a new likely pathogenic variant in LMF1 (c.1527 C > T; p.Pro509=, also expressed as c.1447C>T; p.Gln483*), and a known pathogenic variant in LMF1 (c.779G>A; p.Trp260*). Four participants were heterozygous for variant c.953A>G; p.Asn318Ser in LPL, a known risk factor for hypertriglyceridemia. Participants with variants of unknown significance (VUS) in LMF1 had significantly higher peak TG than those with VUS in other genes. Peak TG were 4317 mg/dL in participants with a history of pancreatitis, and 1769 mg/dL in those without it (p = 0.001). CONCLUSION: Our study identified variants associated with sHTG among Latinos, and showed that genetic variation in LMF1 may be frequently associated with sHTG in this population.