Homozygosity for a mutation in the lipoprotein lipase gene (Gly139-->Ser) causes chylomicronaemia in a boy of Spanish descent.

The enzyme lipoprotein lipase (LPL) plays a crucial role in triglyceride metabolism through catalysis of triglyceride-rich chylomicrons and very low density lipoproteins. Primary LPL deficiency manifests with chylomicronaemia and is caused by mutations in the LPL gene. In this paper we report a novel molecular defect (G670-->A) in exon 4 of the LPL gene, resulting in a substitution of serine for glycine at position 139 in the mature protein. We identified homozygosity for this mutation in a boy of Spanish descent. In vitro mutagenesis provided formal proof that this missense mutation completely abolishes LPL function and therefore is the cause of LPL deficiency.