Lecithin: cholesterol acyltransferase deficiency: identification of two defective alleles in fibroblast cDNA.
Previous mutations associated with lecithin:cholesterol acyltransferase (LCAT) deficiency have been identified using genomic DNA. To facilitate mutation analysis, we used cDNA from cultured fibroblasts which were shown to express LCAT mRNA. Using reverse-transcriptase PCR, LCAT cDNA was obtained from a 13-year-old boy with complete LCAT deficiency, characterized by low HDL-C (3 mg/dl), nondetectable initial cholesterol esterification rate, LCAT activity, and minimal LCAT mass (0.16 vs. 5-7.5 micrograms/ml). Sequencing of LCAT cDNA clones identified two mutations. A novel frameshift mutations caused by deletion of cytosine at the third nucleotide position of amino acid 168 (exon 5) predicts a disrupted protein catalytic site by converting Ser181-->Ala and creates a Pvu-II restriction site prior to premature truncation at amino acid 238. A C-->T transition results in a substitution of methionine for threonine at amino acid position 321 and creates an Nla-III restriction site on the maternal allele. Expression studies of mutant LCAT cDNA confirmed the virtual absence of LCAT activity in transfected COS-1 cells. The molecular defect in a young male with complete LCAT deficiency has been identified using fibroblast cDNA.
Miller
M
M
Department of Medicine, Veterans Administration Medical Center, Baltimore, MD 21201, USA.
Zeller
K
K
Kwiterovich
P C
PC
Albers
J J
JJ
Feulner
G
G
D000293:Adolescent; D000483:Alleles; D001053:Apolipoproteins / Q000097:blood; D001483:Base Sequence; D002478:Cells, Cultured; D002784:Cholesterol / Q000097:blood; D018076:DNA, Complementary / Q000235:genetics*; D004951:Esterification; D005347:Fibroblasts / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D005820:Genetic Testing; D006801:Humans; D007863:Lecithin Cholesterol Acyltransferase Deficiency / Q000097:blood / Q000235:genetics*; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree
D001053:Apolipoproteins; D018076:DNA, Complementary; D008074:Lipoproteins; D002784:Cholesterol