RET genetic screening in patients with medullary thyroid cancer: The Moroccan experience

Background : Germline RET gene mutations are well known to be the genetic causes of multiple endocrine neoplasia type 2 (MEN2) and may be identified by genetic screening.
Aim : The purpose of the present study was to screen nine MTC patients for RET sequence changes.
Materials and Methods : In this study, our sample was composed of 30 individuals: 9 index patients with medullary thyroid carcinoma (MTC) corresponding either to 3 subjects with clinical evidence of MEN2, 6 with apparently sporadic MTC (sMTC), and 21 relatives have been investigated for RET mutations. After DNA extraction from peripheral blood leukocytes, RET exons 8, 10, 11, 13-16 and exon/intron boundaries were analyzed by direct PCR sequencing.
Results : Three different known RET germline mutations in exon 11 (codon 634), p.Cys634Arg (c1900 T→C) (de novo case), p.Cys634Phe (c1901 G→T), p.Cys634Trp (c1902 C→G), were detected in three individuals with MEN2 phenotype. Of the 21 relatives, 2 cases presented mutation. Among the six probands with sMTC, none was found to carry mutation. There was no difference between RET polymorphisms detected among both MEN2 and sMTC patients.
Conclusions : These preliminary data suggest that the RET mutation spectra observed in Moroccan patients with MEN2 are similar to those previously reported in other countries.