Apolipoprotein A I-C III-A IV deficiency

The genes coding for apolipoprotein A-I, apo C-III, A-IV are located on the long arm of chromosome 11. The three genes are tandemly organized. Familial apolipoprotein A-I, C-III, A-IV deficiency was reported. The homozygous proband had extremely low HDL-cholesterol and premature coronary atherosclerosis. Analysis of the abnormal allele revealed the complete deletion of the apo A-I, C-III, A-IV genes. The deletion occurred in areas of repetitive DNA sequence. Familial apolipoprotein A-I, C-III deficiency has been shown to be due to the DNA inversion between the exon 4 of apo A-I and the first intron of apo C-III. The homozygous proband has HDL, deficiency and severe atherosclerosis. RFLP in this gene lesion has been reported and is closely related with the decrease of HDL, hypertriglyceridemia and coronary atherosclerosis. The elucidation of the relation between one particular allele in the lesion of apo A-I, C-III, A-IV gene cluster with lipoprotein metabolism and coronary atherosclerosis will require further determination of the precise nucleotide sequence variation.