A family-based study of hyperinsulinemia and hypertriglyceridemia in heterozygous lipoprotein lipase deficiency.
METHODS
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 (GG(716)C-->GTC/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, nonobese and hyperinsulinemia, manifested mild hypertriglyceridemia (type IV hyperlipoproteinemia). The remaining three healthy heterozygous carriers (two were >40 years old and the other was <40 years old) were all normolipidemic state.


CONCLUSIONS
In this family, hyperinsulinemia as a marker of insulin resistance may be a strong determinant of hypertriglyceridemia in the carrier with heterozygous LPL deficiency.
Ikeda
Yasuyuki
Y
Department of Etiology and Pathophysiology, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan. yikeda@ri.ncvc.go.jp
Takagi
Atsuko
A
Nakata
Yuusei
Y
Sera
Yasuhiko
Y
Hyoudou
Sumio
S
Hamamoto
Kazuko
K
Nishi
Yoshikazu
Y
Yamamoto
Akira
A
D000328:Adult; D000368:Aged; D002675:Child, Preschool; D005192:Family Health; D005260:Female; D005819:Genetic Markers; D006579:Heterozygote; D006801:Humans; D006946:Hyperinsulinism / Q000235:genetics*; D008072:Hyperlipoproteinemia Type I / Q000235:genetics*; D015228:Hypertriglyceridemia / Q000235:genetics*; D007223:Infant; D007333:Insulin Resistance / Q000235:genetics; D007564:Japan; D008071:Lipoprotein Lipase / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D020125:Mutation, Missense / Q000235:genetics; D010375:Pedigree; D022821:RNA Splice Sites / Q000235:genetics
D005819:Genetic Markers; D022821:RNA Splice Sites; D008071:Lipoprotein Lipase