A 17-bp insertion and a Phe215----Cys missense mutation in the dihydrolipoyl transacylase (E2) mRNA from a thiamine-responsive maple syrup urine disease patient WG-34

Biochem Biophys Res Commun. 1991 Jan 31;174(2):804-9. doi: 10.1016/0006-291x(91)91489-y.

Abstract

We have amplified the cDNA for the transacylase (E2) subunit of the branched-chain alpha-ketoacid dehydrogenase (BCKAD) complex from a thiamine-responsive MSUD cell line (WG-34) by the polymerase chain reaction. Sequencing of the amplified WG-34 cDNA showed a 17-bp insertion (AAATACCTTGTTACCAG) apparently resulting from an aberrant splicing of the E2 gene, and a missense (T----G) mutation that changes Phe215 to Cys in the E2 subunit. The existence of these two mutations was confirmed by probing the amplified E2 cDNA or genomic DNA with allele-specific oligonucleotides. The above results support the thesis that the thiamine-responsive MSUD patient (WG-34) is a compound heterozygote at the E2 locus. The implication of the E2 mutations for the thiamine-responsiveness observed in this patient is discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acyltransferases / genetics*
  • Antisense Elements (Genetics)
  • Base Composition
  • Base Sequence
  • Cell Line
  • Cysteine*
  • DNA Transposable Elements*
  • Exons
  • Fibroblasts / enzymology
  • Humans
  • Maple Syrup Urine Disease / drug therapy
  • Maple Syrup Urine Disease / enzymology
  • Maple Syrup Urine Disease / genetics*
  • Molecular Sequence Data
  • Mutation*
  • Phenylalanine*
  • Polymerase Chain Reaction
  • Reference Values
  • Thiamine / therapeutic use*

Substances

  • Antisense Elements (Genetics)
  • DNA Transposable Elements
  • Phenylalanine
  • Acyltransferases
  • dihydrolipoamide acyltransferase
  • Cysteine
  • Thiamine