Mutations and polymorphisms of the gene encoding the beta-subunit of the electron transfer flavoprotein in three patients with glutaric acidemia type II.
Electron transfer flavoprotein (ETF) is a heterodimeric enzyme composed of an alpha-subunit and a beta-subunit and contains a single equivalent of FAD per dimer. ETF deficiency can be demonstrated in individuals affected by a severe metabolic disorder, glutaric acidemia type II (GAII). In this study, we have investigated for the first time the molecular basis of beta-ETF deficiency in three GAII patients: two Japanese brothers, P411 and P412, and a third unrelated patient, P485. Molecular analysis of the beta-ETF gene in P411 and P412 demonstrated that both these patients are compound heterozygotes. One allele is carrying a G to A transition at nucleotide 518, causing a missense mutation at codon 164. This point mutation is maternally derived and is not detected in 42 unrelated controls. The other allele carries a G to C transversion at the first nucleotide of the intron donor site, downstream of an exon that is skipped during the splicing event. The sequence analysis of the beta-ETF coding sequence in P485 showed only a C to T transition at nucleotide 488 that causes a Thr154 to Met substitution and the elimination of a HgaI restriction site. HgaI restriction analysis on 63 unrelated controls' genomic DNA demonstrated that the C488T transition identifies a polymorphic site. Finally, transfection of wild-type beta-ETF cDNA into P411 fibroblasts suggests that wild-type beta-ETF cDNA complements the genetic defect and restores the beta-oxidation flux to normal levels.
Colombo
I
I
Istituto di Fisiologia Generale e Chimica Biologica, Facoltà di Farmacia, Università degli Studi di Milano, Italy.
Finocchiaro
G
G
Garavaglia
B
B
Garbuglio
N
N
Yamaguchi
S
S
Frerman
F E
FE
Berra
B
B
DiDonato
S
S
D000592:Amino Acid Metabolism, Inborn Errors / Q000097:blood / Q000235:genetics*; D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D004247:DNA; D015257:DNA-Cytosine Methylases / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D044927:Electron-Transferring Flavoproteins; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005420:Flavoproteins / Q000737:chemistry / Q000235:genetics*; D005977:Glutarates / Q000097:blood*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010084:Oxidation-Reduction; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D017384:Sequence Deletion; D014162:Transfection
D044927:Electron-Transferring Flavoproteins; D005420:Flavoproteins; D005977:Glutarates; D004247:DNA; C054689:DNA modification methylase HgaI; D015257:DNA-Cytosine Methylases; C024388:CTGCAG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific; C035736:glutaric acid