However, because the neuroendocrine tumor-associated RET mutations are clustered among the cysteine residues in exons 10 and 11 (and, in the case of MEN 2B, a single methionine codon in exon 16), a simple and rapid assay should be possible.
As stated, although the common MEN 2B mutation in exon 16 (M918T) removes a Fok I site and could therefore be easily analyzed by restriction digest, exons 10 and 11 harbor a variety of mutations in multiple codons in MEN 2A and MTC patients (see Table 1 in reference 11).
We have adapted this technique to detect mutations in exons 10, 11, and 16 associated with inherited MTC (MEN 2A, MEN 2B, or FMTC).
All of the patients had inherited MTC (MEN 2A, MEN 2B, or FMTC) and had known genomic RET mutations previously analyzed by sequence analysis (by S.N.T.
The single known exon 16 mutation associated with MEN 2B and sporadic MTC was identified by the Phastgel system at an electrophoretic temperature of 4[degrees]C (Fig.