Mutations in the lipoprotein lipase gene as a cause of hypertriglyceridemia and pancreatitis in Taiwan

Introduction: Familial lipoprotein lipase (LPL) deficiency is inherited as an autosomal recessive trait and is characterized by chylomicronemia, eruptive xanthoma, hepatosplenomegaly, and recurrent pancreatitis. Aims and Methodology: Two unrelated Chinese of Han descent with hypertriglyceridemia were enrolled in this study, and another six Han Chinese with no family history of hypertriglyceridemia and diabetes were recruited as normal controls. LPL activity was determined with use of an artificial substrate of C-14-trioleine and Arabic gum, and release of C-14 free fatty acid was determined by the liquid-liquid partitioning system. LPL mass was measured by enzyme immunoassay. Genomic DNA was extracted from EDTA-preserved whole blood, and PCR was used to amplify the nine coding exons and the minimal promoter of the LPL gene. Results: DNA sequence analysis revealed that mutations were identified in both patients; one patient had compound heterozygous mutations in codon 252 [CTG( Leu) --> GTG( Val)] and in codon 264 [TGC(Cys) --> TGa(Ter)] of exon 6, and the other patient had homozygous L252V mutation. These subjects had greater than or equal to 90% reduction in LPL mass and greater than or equal to60% reduction in LPL activity. Conclusion: The mutated and truncated LPLs caused hypertriglyceridemia in these patients in Taiwan with hypertriglyceridemia and pancreatitis.