Apolipoprotein CII (apo CII) gene expression defect in an individual with familial apo CII deficiency.

We have examined the expression of the apolipoprotein CII (apo CII) gene in an individual with familial apo CII (apo CII) deficiency. Total RNA was prepared from this patient's liver tissue and analysed in Slot Blot and Northern Blot experiments using a cloned apo CII cDNA as a probe. In this patient, there is at least a four-fold decrease in the level of apo CII mRNA, when compared to liver tissue from a control individual. The residual apo CII mRNA detected in this patient is of normal length. These results suggest that the failure to detect apo CII protein in this patient's serum is not due to a failure to transcribe or process apo CII mRNA, but probably to a defect in the translation of the apo CII message. This defect results in partial degradation of the apo CII message leading to the much reduced levels which we have observed.