Two alpha subunit donor splice site mutations cause human trifunctional protein deficiency.
Human trifunctional protein catalyzes three steps in mitochondrial beta-oxidation of fatty acids, including the long chain 3-hydroxyacyl-CoA dehydrogenase step. Deficiency of this heterocomplex, which contains 4 alpha and 4 beta subunits, causes sudden unexplained infant death, a Reye-like syndrome, cardiomyopathy, or skeletal myopathy. We determined the molecular basis of this deficiency in a patient with neonatal presentation and later sudden death using reverse transcription and PCR amplification of his alpha subunit mRNA. We demonstrated a universal deletion of exon 3 (71 bp) in his mRNA. This deletion causes a frameshift and very early premature termination. Amplification of genomic DNA demonstrated that the patient was a compound heterozygote with two different mutations in the 5' donor splice site following exon 3: a paternally inherited G to A transversion at the invariant position +1 and a maternally inherited A to G mutation at position +3. Both allelic mutations apparently cause exon 3 skipping, resulting in undetectable levels of alpha subunit protein, and complete loss of trifunctional protein. This is the initial molecular characterization of trifunctional protein deficiency.
Brackett
J C
JC
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.
Sims
H F
HF
Rinaldo
P
P
Shapiro
S
S
Powell
C K
CK
Bennett
M J
MJ
Strauss
A W
AW
D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000172:deficiency / Q000235:genetics*; D017398:Alternative Splicing; D001483:Base Sequence; D002264:Carboxylic Acids / Q000652:urine; D002585:Cesarean Section; D002849:Chromatography, Gas; D017931:DNA Primers; D003645:Death, Sudden; D005091:Exons; D005227:Fatty Acids / Q000652:urine; D005260:Female; D006579:Heterozygote; D006801:Humans; D007231:Infant, Newborn; D007438:Introns; D046911:Macromolecular Substances; D008297:Male; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D017384:Sequence Deletion
D002264:Carboxylic Acids; D017931:DNA Primers; D005227:Fatty Acids; D046911:Macromolecular Substances; D015094:3-Hydroxyacyl CoA Dehydrogenases