Human Genetics

, Volume 111, Issue 6, pp 501–510

Intronic mutations outside of Alu-repeat-rich domains of the LDL receptor gene are a cause of familial hypercholesterolemia

  • Sabine Amsellem
  • Dorothée Briffaut
  • Alain Carrié
  • Jean Rabès
  • Jean Girardet
  • Alexandre Fredenrich
  • Philippe Moulin
  • Michel Krempf
  • Yves Reznik
  • Bernard Vialettes
  • Jean de Gennes
  • Eric Brukert
  • Pascale Benlian
Original Investigation

DOI: 10.1007/s00439-002-0813-4

Cite this article as:
Amsellem, S., Briffaut, D., Carrié, A. et al. Hum Genet (2002) 111: 501. doi:10.1007/s00439-002-0813-4

Abstract.

Familial hypercholesterolemia (FH), a frequent monogenic condition complicated by premature cardiovascular disease, is characterized by high allelic heterogeneity at the low-density lipoprotein receptor (LDLR) locus. Despite more than a decade of genetic testing, knowledge about intronic disease-causing mutations has remained limited because of lack of available genomic sequences. Based on the finding from bioinformatic analysis that Alu repeats represent 85% of LDLR intronic sequences outside exon-intron junctions, we designed a strategy to improve the exploration of genomic regions in the vicinity of exons in 110 FH subjects from an admixed population. In the first group of 42 patients of negative mutation carriers, as previously established by former screening strategies (denaturing gradient gel electrophoresis, DNA sequencing with former primers overlapping splice-sites, Southern Blotting), about half (n=22) were found to be carriers of at least one heterozygous mutation. Among a second group of 68 newly recruited patients, 27% of mutation carriers (n=37) had a splicing regulatory mutation. Overall, out of the 54 mutations identified, 13 were intronic, and 18 were novel, out of which nearly half were intronic. Two novel intronic mutations (IVS8–10G→A within the polypyrimidine tract and IVS7+10G→A downstream of donor site) might create potential aberrant splice sites according to neural-network computed estimation, contrary to 31 common single nucleotide variations also identified at exon-intron junctions. This new strategy of detecting the most likely disease-causing LDLR mutations outside of Alu-rich genomic regions reveals that intronic mutations may have a greater impact than previously reported on the molecular basis of FH. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00439-002-0813-4

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Sabine Amsellem
    • 1
  • Dorothée Briffaut
    • 1
  • Alain Carrié
    • 2
  • Jean Rabès
    • 3
  • Jean Girardet
    • 4
  • Alexandre Fredenrich
    • 5
  • Philippe Moulin
    • 6
  • Michel Krempf
    • 7
  • Yves Reznik
    • 8
  • Bernard Vialettes
    • 9
  • Jean de Gennes
    • 10
  • Eric Brukert
    • 10
  • Pascale Benlian
    • 1
  1. 1.Department of Biochemistry and Molecular Biology, APHP Saint Antoine Hospital, Paris, France
  2. 2.Department of Biochemistry, APHP Pitié Salpétrière Hospital, Paris
  3. 3.Department of Biochemistry, APHP Ambroise Paré Hospital, Boulogne Billancourt, France
  4. 4.Department of Pediatrics, APHP Trousseau Hospital, Paris, France
  5. 5.Department of Metabolic Diseases, Pasteur Hospital, Nice, France
  6. 6.Department of Metabolic Diseases, Antiquaille Hospital, Lyon, France
  7. 7.Department of Metabolic Diseases, Hotel Dieu Hospital, Nantes, France
  8. 8.Department of Metabolic Diseases, Côte de Nacre Hospital, Caen, France
  9. 9.Department of Metabolic Diseases, Sainte Marguerite Hospital, Marseille
  10. 10.Department of Metabolic Diseases, APHP Pitié Salpétrière Hospital, Paris, France
  11. 11.Laboratoire Commun de Biologie Moléculaire, Hôpital Saint Antoine, 184 Rue du Faubourg Saint Antoine, F-75012 Paris, France