Pseudo-hypertriglyceridaemia: a measurement artefact due to glycerol kinase deficiency.

A man presented with elevated plasma triglycerides and was commenced on fibrate treatment. The triglycerides did not fall and compliance was questioned. The triglyceride elevation was inconsistent with the observed lack of turbidity in the plasma sample. Triglyceride elevation was not confirmed by a different analytical method and lipoprotein electrophoresis showed a normal very low density lipoprotein (VLDL) band pattern. Glycerol kinase deficiency was suspected and was supported by elevated urine glycerol, and confirmed by reduced leucocyte enzyme activity and mutational analysis of the GK gene which showed a novel three base pair deletion. Demonstration of a point mutation also excludes a contiguous gene deletion syndrome.