Objective: To identify the genotype of RET gene in one multiple endocrine neoplasia type 2A (MEN2A) kindred.
Methods: Genome DNA was extracted from peripheral blood leucocytes. The DNA sequence of gel-purified polymerase chain reaction (PCR) products was determined with the previously reported 6 pairs of primers of PCR amplification of 10, 11, 13, 14, 15, and 16 exons of RETgene.
Results: No abnormalities were found in exon 10, 13, 14, 15, and 16. C to G replacement in nucleotide 14 996 of exon 11 was identified in DNA samples obtained from both peripheral blood of 2 affected brothers. This missense point mutation arisen in heterozygosity and caused a substitution of Cys to Trp residue at codon 634 ( Cys 634 Trp) in RET protein.
Conclusion: The genotype of the family is identified as Cys 634 Trp substitution of RET gene.