A dinucleotide mutation in the endothelin-B receptor gene is associated with lethal white foal syndrome (LWFS); a horse variant of Hirschsprung disease

Hum Mol Genet. 1998 Jun;7(6):1047-52. doi: 10.1093/hmg/7.6.1047.


Lethal white foal syndrome (LWFS) is a congenital anomaly of horses characterized by a white coat colour and aganglionosis of the bowel, which is similar to Hirschsprung disease (HSCR). We decided to investigate possible mutations of the endothelin-B receptor gene ( EDNRB ) in LWFS as recent studies in mutant rodents and some patients have demonstrated EDNRB defects. First, we identified a full-length cDNA for horse EDNRB . This cDNA fragment contained a 1329 bp open reading frame which encoded 443 amino acid residues. The predicted amino acid sequence was 89, 91 and 85% identical to human, bovine and mouse as well as rat EDNRB respectively, but only 55% identical to the human, bovine and rat endothelin A receptor (EDNRA). Secondly, sequence analysis, together with allele-specific PCR and the amplification-created restriction site (ACRS) technique, revealed a dinucleotide TC-->AG mutation, which changed isoleucine to lysine in the predicted first transmembrane domain of the EDNRB protein. This was associated with LWFS when homozygous and with the overo phenotype when heterozygous.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA Mutational Analysis
  • DNA, Complementary
  • Hirschsprung Disease / genetics
  • Hirschsprung Disease / veterinary*
  • Horse Diseases / genetics*
  • Horses
  • Humans
  • Molecular Sequence Data
  • Mutation*
  • Nucleotides
  • Receptor, Endothelin B
  • Receptors, Endothelin / genetics*
  • Sequence Homology, Amino Acid


  • DNA, Complementary
  • Nucleotides
  • Receptor, Endothelin B
  • Receptors, Endothelin

Associated data

  • GENBANK/AF019072