Somatic trinucleotide change encompassing codons 882 and 883 of the RET proto-oncogene in a patient with sporadic medullary thyroid carcinoma.
OBJECTIVE
Restriction analysis is a straightforward procedure for mutational analysis. It is commonly used for screening RET mutations. Incomplete digestion is a well-known cause of false results. Herein, we report another limitation of the method.


METHODS
Screening for somatic mutations in RET exons 16, 13 and 15 was performed in a patient with a sporadic medullary thyroid carcinoma. Genetic study was carried out by both restriction analysis and direct sequencing.


RESULTS
A somatic trinucleotide change encompassing codons 882 and 883 of the RET proto-oncogene (GTA GCT to GTT TTT) was documented. Particular to this case is the silent mutation (GTA-->GTT) at codon 882. Independently, both the novel silent mutation and the missense mutation at codon 883 may disrupt the same AluI restriction site. Based on the restriction pattern we were able to say that both mutations occurred in the same allele.


CONCLUSIONS
Restriction analysis is an easy approach for screening RET mutations; however, it is not enough to assign a final diagnosis.
Bugalho
M J
MJ
Department of Endocrinology/Laboratory of Molecular Biology, Portuguese Cancer Institute, 1093-Lisbon Codex, Portugal. bugalho@mail.telepac.pt
Coelho
I
I
Sobrinho
L G
LG
D000328:Adult; D000483:Alleles; D001483:Base Sequence / Q000235:genetics; D018276:Carcinoma, Medullary / Q000235:genetics*; D003062:Codon / Q000235:genetics*; D004252:DNA Mutational Analysis; D029721:Drosophila Proteins; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics; D020125:Mutation, Missense / Q000235:genetics; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D015183:Restriction Mapping; D013964:Thyroid Neoplasms / Q000235:genetics*
D003062:Codon; D029721:Drosophila Proteins; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila