title: Donor splice site mutation in the apolipoprotein (Apo) C-II gene (Apo C-IIHamburg) of a patient with Apo C-II deficiency.
abstract: The DNA, RNA, and protein of apo C-II have been analyzed in a patient with apo C-II deficiency (apo C-IIHamburg). Markedly reduced levels of plasma and intrahepatic C-II apolipoprotein were demonstrated by immunoblotting and immunohistochemical analysis. Northern, slot blot, and in situ hybridization studies revealed low levels of a normal-sized apo C-II mRNA. No major rearrangement of the apo C-II gene was detected by Southern blotting. Sequence analysis of apo C-II genomic clones revealed a G-to-C substitution within the donor splice site of intron II. This base substitution resulted in the formation of a new Dde I and loss of a Hph I restriction enzyme cleavage site. Amplification of the mutant sequence by the polymerase chain reaction and digestion with Dde I and Hph I restriction enzymes established that the patient was homozygous for the G-to-C mutation. This is the initial report of the DNA sequence of an abnormal apo C-II gene from a patient with deficiency of apo C-II. We propose that this donor splice site mutation is the primary genetic defect that leads to defective splicing and ultimately to an apo C-II deficiency in this kindred.
authors.affiliation: Molecular Disease Branch, National Heart, Lung and Blood Institute, Bethesda, Maryland 20892.
authors.forename: S S
authors.initials: SS
authors.lastname: Fojo
authors.forename: U
authors.initials: U
authors.lastname: Beisiegel
authors.forename: U
authors.initials: U
authors.lastname: Beil
authors.forename: K
authors.initials: K
authors.lastname: Higuchi
authors.forename: M
authors.initials: M
authors.lastname: Bojanovski
authors.forename: R E
authors.initials: RE
authors.lastname: Gregg
authors.forename: H
authors.initials: H
authors.lastname: Greten
authors.forename: H B
authors.initials: HB
authors.lastname: Brewer
mesh_terms: D000328:Adult; D053304:Apolipoprotein C-II; D001056:Apolipoproteins C / Q000172:deficiency / Q000235:genetics*; D001483:Base Sequence; D015139:Blotting, Southern; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D005260:Female; D005784:Gene Amplification; D006801:Humans; D009154:Mutation; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D053304:Apolipoprotein C-II; D001056:Apolipoproteins C; D012333:RNA, Messenger; C027908:endodeoxyribonuclease DdeI; D015252:Deoxyribonucleases, Type II Site-Specific; C024412:GGTGA-specific type II deoxyribonucleases