Untying the Next Genetic Thread in a Family With MEN2A Syndrome: A Case Report

Multiple endocrine neoplasia type 2A (MEN2A) is a rare autosomal dominant syndrome characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, and primary hyperparathyroidism. Early genetic screening is crucial for timely intervention. We report a familial case of MEN2A involving four affected members across two generations. The index patient, a 40‐year‐old male with prior MTC and pheochromocytoma, presented with recurrent adrenal disease. His 41‐year‐old sister was diagnosed with MTC and pheochromocytoma despite negative genetic testing. The youngest sibling (37 years) and the index patient's 18‐year‐old son were diagnosed with MTC, with the former testing positive for a RET mutation. All underwent appropriate surgeries with ongoing surveillance. This case highlights the variable clinical presentation and genetic penetrance of MEN2A within a single family. It underscores the importance of genetic screening in all MTC patients and their first‐degree relatives, as early identification of asymptomatic carriers enables timely prophylactic interventions.