G691S/S904S polymorphism in the  RET protooncogene of a 25-year-old medical student with bilateral pheochromocytoma

The case of a 25-year-old medical student with bilateral pheochromocytoma is described. Following diagnostic testing, tumors were surgically removed. Genetic analysis revealed that the patient is a heterozygote with the following mutations on opposite homologs: G691S (exon 11) and S904S (TCC-TCG, exon 15), suggesting the diagnosis of multiple endocrine neoplasia 2A (MEN2A). A diagnosis of MEN2 would be an indication of thyroidectomy in this patient. Although this mutation is described in the literature, it has no known connection to pheochromocytomas. Therefore, it is unknown whether there is a causal connection between the G691S genotype and the pheochromocytomas in this patient. If so, G691S is to be added to the list of genotypes causing MEN2A. Here, the procedure of sequencing the RET protooncogene is described and a possible association between the G691S genotype and MEN2A is discussed.