A family-based study of hyperinsulinemia and hypertriglyceridemia in heterozygous lipoprotein lipase deficiency

Case report: A case is presented of predisposing a patient's father with obligate heterozygous lipoprotein lipase (LPL) deficiency to mild hypertriglyceridemia in Japanese I-family members ( n=8) with patient DI, who was a compound heterozygote for a novel missense mutation of G154V (G G 716C→G T C/Gly 154 Val) in exon 5 and a novel splice mutation (Int8/5′-dss/t(+2)c; a T-to-C transition in the invariant GT at position +2 of the 5′ donor splice site (dss)) in intron 8 of the LPL gene. Results: The patient's father and paternal grandmother were heterozygotes for the Int8/5′-dss/t(+2)c allele, while the patient's mother and maternal grandmother were heterozygotes for the G154V allele. These four heterozygous carriers with one defective LPL allele showed 45–57% of the mean LPL activity and mass in the post-heparin plasma (PHP) observed in normal individuals. Among the four heterozygous carriers, the patient's father, who was 40 years old and the other was