The Genetics of Familial Neoplastic Thyroid Disease and Primary Hyperparathyroidism.

Inherited thyroid and parathyroid diseases represent a small but clinically significant subset of endocrine neoplasms, often associated with identifiable genetic mutations. Familial medullary thyroid cancer is linked to RET mutations and frequently occurs with multiple endocrine neoplasia syndromes, requiring early diagnosis and prophylactic intervention. Nonmedullary familial thyroid cancers are more heterogenous with unclear genetic drivers and variable inheritance patterns. Syndromic forms carry increased thyroid cancer risk necessitating targeted surveillance. Familial parathyroid disease presents earlier than sporadic disease and carries important implications for management and surveillance. Comprehensive clinical evaluation, risk stratification, and family screening are essential for optimal management and outcomes.