Eng et al. reported that the frequency of CLA in MEN 2A families was approximately 9% (18/199), and all 18 families were frequently associated with RET codon 634 mutation, but there was no specific analysis of the correlation between the RET genotype and CLA phenotype or of case distribution of CLA in each family [15]. The gene discussed is RET; the disease is multiple endocrine neoplasia type 2A.