A novel mutation in the intron 1 splice donor site of the cholesterol ester transfer protein (CETP) gene as a cause of hyperalphalipoproteinemia.
The exchange of cholesterol ester (CE) between lipoproteins occurs through the action of cholesterol ester transfer protein (CETP). The human CETP gene is composed of 16 exons encompassing 25 kbp on chromosome 16q13. The objective of this study was to determine whether a mutation in the CETP gene accounted for severe hyperalphalipoproteinemia in an 80-year-old subject. As a secondary objective, we also investigated the allelic frequency of D442G and Int14A mutation in 224 random Han Chinese subjects. DNA sequence analysis of the CETP gene in the patient revealed a peculiar nucleotide pattern in intron 1. To determine whether this peculiarity results in abnormally spliced mRNA, we used reverse-transcriptase polymerase chain reaction (RT-PCR) to amplify and sequence the patient's cDNA using CETP-specific primers that spanned this splice junction. Both the wild-type and mutant cDNA were detected, and the mutant cDNA showed that its 5'-splice site shifted 4 nucleotides upstream. This change results in a frame-shift and premature termination at amino acid residue 22, and thus predicts a markedly truncated protein product. Although this patient did not have either the D442G or Int14A allele, we found that the allelic frequency of D442G in 224 subjects was 4.46%. No subjects had the Int14A allele. In conclusion, a novel intron 1 splice site mutation in the CETP gene in 1 patient with hyperalphalipoproteinemia and D442G allelic frequency of 4.46% was found among a normal population in Taiwan.
Jap
Tjin-Shing
TS
Section of Biochemistry, Department of Pathology and Laboratory Medicine, Veterans General Hospital-Taipei, Faculty of Medical Technology, National Yang-Ming University, Taiwan, ROC.
Wu
Yi-Chi
YC
Tso
Yi-Chu
YC
Chiu
Chih-Yang
CY
D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000595:Amino Acid Sequence / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D053480:Cholesterol Ester Transfer Proteins; D004274:DNA, Recombinant; D005787:Gene Frequency; D006023:Glycoproteins; D006801:Humans; D007438:Introns / Q000235:genetics*; D008075:Lipoproteins, HDL / Q000097:blood*; D008297:Male; D009154:Mutation / Q000502:physiology*; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction
C506642:CETP protein, human; D002352:Carrier Proteins; D053480:Cholesterol Ester Transfer Proteins; D004274:DNA, Recombinant; D006023:Glycoproteins; D008075:Lipoproteins, HDL