Cancer predisposition syndromes are entities determined especially by germinal pathogenic variants, with most of them autosomal dominantly inherited. The risk of a form of cancer is variable throughout life and affects various organs, including the thyroid. Knowing the heterogeneous clinical picture and the existing genotype–phenotype correlations in some forms of thyroid cancer associated with these syndromes is important for adequate and early management of patients and families. This review synthesizes the current knowledge on genes and proteins involved in cancer predisposition syndromes with thyroid cancer and the phenomena of heterogeneity (locus, allelic, mutational, and clinical).

Acromegaly is a rare endocrine disorder characterized by the excessive production of growth hormone (GH) in adulthood. Currently, it is understood that certain pituitary neuroendocrine tumors (PitNETs) exhibit a hereditary predisposition. These tumors’ genetic patterns fall into two categories: isolated and syndromic tumors. The isolated forms are characterized by molecular defects that predispose exclusively to PitNETs, including familial isolated pituitary adenomas (FIPAs) and sporadic genetic defects not characterized by hereditary predisposition. All the categories involve either germline or somatic mutations, or both, each associated with varying levels of penetrance and different phenotypes. This highlights the importance of genetic testing and the need for a more comprehensive view of the whole disease. Despite the availability of multiple treatment options, diagnosis often occurs after several years, and management is still difficult. Early detection and intervention are crucial for preventing complications and enhancing the quality of life for affected individuals. This review aims to elucidate the molecular, clinical, and histological characteristics of GH-secreting PitNETs, providing insights into their prevalence, treatment nuances, and the benefits of genetic testing for each type of genetic disorder associated with acromegaly.