Identification of the mutation responsible for a case of plasmatic apolipoprotein CII deficiency (Apo CII-Bari).

We studied a case of familial Apolipoprotein CII deficiency. By Southern hybridization, amplification and sequence analysis, the genetic defect was identified. It consists in a point mutation C- greater than G in the third exon of the gene causing a premature stop codon. Truncated at the aa. 36 of the mature form, the protein loses its functional domains, becomes inefficient and cannot be detected in the plasma, because of its high instability. The mutation destroys an RsaI site, present in the normal gene sequence. This point mutation is useful in the diagnosis of this Apolipoprotein CII deficiency.