Papillary Thyroid Carcinoma in a Patient With a Germline Titin (TTN) Mutation

The titin (TTN) gene encodes the largest known human protein and is essential in maintaining cardiac sarcomere structure. Germline TTN mutations are strongly linked to dilated cardiomyopathy and arrhythmias, and emerging evidence suggests a possible relationship between TTN alterations and oncologic processes. Owing to the large size of the TTN gene, recurrent mutations are frequently observed across cancer datasets, but the clinical and biological significance of these alterations, particularly in the germline setting, remains incompletely understood. This case presents a patient with a germline TTN mutation who was diagnosed with papillary thyroid carcinoma after he developed amiodarone-induced thyrotoxicosis.