A new hot spot for mutations in the ret protooncogene causing familial medullary thyroid carcinoma and multiple endocrine neoplasia type 2A

J Clin Endocrinol Metab. 1998 Mar;83(3):770-4. doi: 10.1210/jcem.83.3.4619.


One hundred and eighty-one families with multiple endocrine neoplasia type 2A (MEN-2A) or familial medullary thyroid carcinoma (FMTC) have been investigated for mutations in the ret protooncogene in Germany. In 8 families with FMTC or MEN-2A, no mutation could be detected in the cysteine-rich domain encoded in exons 10 and 11 of the ret protooncogene. DNA sequencing of additional exons (no. 13-15) revealed rare noncysteine mutations in 3 families (codons 631, 768, and 844). In contrast to these rare events, heterozygous missense mutations in exon 13, codons 790 and 791, were found in 5 families (4 with MTC only; 1 family with MTC and pheochromocytoma) and 11 patients with apparently sporadic tumors. Two different mutations in codon 790 (TTG-->TTT, TTG-->TTC; Leu790Phe) and one mutation in codon 791 (TAT-->TTT; Tyr791Phe) created a phenylalanine residue. We conclude that codons 790 and 791 of the ret protooncogene represent a new hot spot for FMTC/MEN-2A causing mutations. With the discovery of these considerably common mutations in codons 790 and 791 and the identification of some rare mutations, 100% of the German FMTC/MEN-2A families could be characterized by a mutation in the ret protooncogene.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Amino Acid Sequence
  • Base Sequence
  • Carcinoma, Medullary / genetics*
  • Codon / genetics
  • DNA, Neoplasm / genetics
  • Drosophila Proteins*
  • Exons / genetics
  • Female
  • Humans
  • Male
  • Middle Aged
  • Multiple Endocrine Neoplasia Type 2a / genetics*
  • Mutation / genetics*
  • Pedigree
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins c-ret
  • Receptor Protein-Tyrosine Kinases / genetics*
  • Thyroid Neoplasms / genetics*


  • Codon
  • DNA, Neoplasm
  • Drosophila Proteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-ret
  • Receptor Protein-Tyrosine Kinases
  • Ret protein, Drosophila