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.
J C Brackett, H F Sims, P Rinaldo, S Shapiro, C K Powell, M J Bennett, A W Strauss
Guidelines: The Editorial Board will only consider letters that we deem relevant and of interest to our readers. We will not post data that have not been subjected to peer review, nor will we post letters that are essentially a reiteration of another letter. All accepted letters will be posted on our website within one week of acceptance. We reserve the right to edit any letter for length, content, and clarity. Authors of all accepted letters will be asked to preview any changes. Authors will be notified by e-mail if their letters were not accepted. As this is a final decision, no appeals will be considered.
Specific requirements: All letters must be 400 words or fewer. You may enter the letter as plain text or HTML. The author's name and e-mail address are required, and will be posted with the letter. All possible conflicts of interest must be noted, even if they are not posted. If you wish to include a figure (keep in mind that non-peer-reviewed data will not be posted), please contact the editors directly at email@example.com.