Genetic polymorphisms and mutations of the lipoprotein lipase gene in Japanese schoolchildren with hypoalphalipoproteinemia.

Lipoprotein lipase (LPL) is an important enzyme for the hydrolysis of TG on lipoproteins, and its activity is positively correlated with the plasma levels of high density lipoprotein cholesterol (HDL-C). To investigate the association between the LPL gene and low HDL-C levels, we studied two polymorphisms (Hind III and Pvu II) and three mutations (Asn291Ser, Gly188Glu and LPL(Arita)) of the LPL gene in 114 children with low HDL-C levels (<40 mg/dl) and 194 control children using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques (PCR-RFLP). The frequency of the Pvu II +/+ genotype was significantly higher in the children with low-HDL/high-TG (TG>100 mg/dl, 90th percentile level among Japanese schoolchildren) than in the other children (vs the low-HDL/normal-TG children, chi2 = 7.49, p < 0.01; vs control children, chi2 = 7.23, p < 0.01). Pvu II+ allele of the LPL gene was associated with elevated TG levels in low HDL-C groups. In addition, we found one heterozygote of LPL(Arita) (deletion of G at base 916 in exon 5, the most common mutation of LPL deficiency in Japanese), among the low-HDL/high-TG subjects. The other two variants were not detected in either the low-HDL children or control children. LPL Asn291Ser and Gly188Glu have been presumed to be rare in the Japanese population. In conclusion, our results suggest that hypoalphalipoproteinemia with elevated TG level may be associated with genetic variations of the LPL gene.