Two germline missense mutations at codons 804 and 806 of the RET proto-oncogene in the same allele in a patient with multiple endocrine neoplasia type 2B without codon 918 mutation

Jpn J Cancer Res. 1999 Jan;90(1):1-5. doi: 10.1111/j.1349-7006.1999.tb00658.x.


Multiple endocrine neoplasia (MEN) type 2B is a clinically distinct entity among the autosomal dominant MEN 2 syndromes. Most patients with MEN 2B carry a germline mutation (M918T) of the RET proto-oncogene, while a few carry A883F. We examined a patient with MEN 2B, but without M918T or A883F, and her relatives. Here, we report the presence in this patient of 2 germline mutations, V804M and Y806C in the same allele. While the novel Y806C was inherited from her father, its carriers (her father and brother) was not affected by MEN 2. In contrast, V804M was a de novo mutation, that has been reported in patients with familial medullary thyroid carcinoma. Combinations of mutations of the RET proto-oncogene may cause oncogenic activities different from those of single mutations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Codon / genetics
  • Drosophila Proteins*
  • Exons
  • Female
  • Germ-Line Mutation*
  • Humans
  • Male
  • Multiple Endocrine Neoplasia Type 2b / genetics*
  • Mutation, Missense*
  • Pedigree
  • Polymerase Chain Reaction
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins c-ret
  • Proto-Oncogenes*
  • Receptor Protein-Tyrosine Kinases / genetics*
  • Valine


  • Codon
  • Drosophila Proteins
  • MAS1 protein, human
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-ret
  • Receptor Protein-Tyrosine Kinases
  • Ret protein, Drosophila
  • Valine