Molecular genetics in primary hyperparathyroidism: the role of genetic tests in differential diagnosis, disease prevention strategy, and therapeutic planning. A 2017 update.

Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine disease in developed countries. It mainly occurs as sporadic cases (about 90-95% of cases), while only the remaining 5-10% is represented by familial inherited parathyroid disorders due to causative mutations in specific target genes. Clinical variability among the different familial parathyroid syndromes is generally linked to the specific mutated gene and it can predispose subjects to different manifestations of parathyroid pathology, various degrees of PHPT severity, persistence and/or after-surgery recurrences. Genetic tests is helpful in differential diagnosis favouring the recognition of the specific familial PHPT syndrome and, subsequently, in planning the most suitable surgical procedures and/or pharmacological interventions. Moreover, genetic test is important to recognise mutation carriers, within PHPT familial forms, even before the appearance of biochemical and/or clinical symptoms. This review resumes general concepts about genetic diagnosis of PHPT in familial hereditary syndromes, specifically describing why, when, and which genetic screenings should be performed in every specific PHPT-associated parathyroid disease.