Splicing Defects in ABCD1 Gene Leading to Both Exon Skipping and Partial Intron Retention in X-linked Adrenoleukodystrophy Tunisian Patient

Neurosci Res. 2015 Aug;97:7-12. doi: 10.1016/j.neures.2015.03.005. Epub 2015 Mar 31.

Abstract

X-linked adrenoleukodystrophy (X-ALD) affects the nervous system white matter and adrenal cortex secondary to mutations in the ABCD1 gene that encodes a peroxisomal membrane protein: the adrenoleukodystrophy protein. The disease is characterized by high concentrations of very long-chain fatty acids in plasma, adrenal, testicular and nervous tissues. Various types of mutations have been identified in the ABCD1 gene: point mutations, insertions, and deletions. To date, more than 40 point mutations have been reported at the splice junctions of the ABCD1 gene; only few functional studies have been performed to explore these types of mutations. In this study, we have identified de novo splice site mutation c.1780+2T>G in ABCD1 gene in an X-ALD Tunisian patient. Sequencing analysis of cDNA showed a minor transcript lacking exon 7 and a major transcript with a partial intron 7 retention due to activation of a new intronic cryptic splice site. Both outcomes lead to frameshifts with premature stop codon generation in exon 8 and intron 7 respectively. To the best of our knowledge, the current study demonstrates that a single splicing mutation affects the ABCD1 transcripts and the ALDP protein function.

Keywords: ABCD1 gene; Adrenal insufficiency; Exon skipping; Intron retention; X-ALD; mRNA splicing.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily D, Member 1
  • ATP-Binding Cassette Transporters / genetics*
  • Adolescent
  • Adrenoleukodystrophy / genetics*
  • Adrenoleukodystrophy / pathology
  • Brain / pathology
  • Exons*
  • Humans
  • Introns*
  • Male
  • Mutation
  • Tunisia

Substances

  • ABCD1 protein, human
  • ATP Binding Cassette Transporter, Subfamily D, Member 1
  • ATP-Binding Cassette Transporters