Syndrome Mean age of onset Parathyroid pathology Clinical treatment
MEN1 20-25 years Multiglandular hyperplasia and/or adenoma Subtotal parathyroidectomy of hyperplastic and/or adenomatous parathyroids; or total parathyroidectomy with healthy tissue reimplantation in the non-dominant forearm, in case of  pathological involvement of all four parathyroids
MEN2A Over 30 years Single or multiglandular hyperplasia and/or adenoma Specific resection on only the hyperplastic and/or adenomatous parathyroids
MEN4 Over 45 years Single or multiglandular hyperplasia and/or adenoma Specific resection on only the hyperplastic and/or adenomatous parathyroids
FHH All ages Multiglandular mildly hyperplastic parathyroids Parathyroidectomy is not only unnecessary but also inappropriate, since it does not cure FHH-associated hypercalcemia
NSHPT At birth or within the first six months of life Multiglandular markedly hyperplastic parathyroids Total parathyroidectomy
HPT-JT Over 30 years Single or multiglandular (usually two glands)  cystic adenoma.
Carcinomas in 10-15% of cases
Subtotal parathyroidectomy of adenomatous and/or carcinomatous  parathyroids, or total parathyroidectomy, with healthy tissue reimplantation in the non-dominant forearm, in case of  adenoma involvement of all four parathyroids.
FIPH N.R. Single or multiglandular adenoma Subtotal parathyroidectomy of adenomatous parathyroids, or total parathyroidectomy, with healthy tissue reimplantation in the non-dominant forearm, in case of  adenoma involvement of all four parathyroids.
Footnotes: N.R.=not reported
Table 1: Main clinical characteristics of familial hereditary forms of PHPT.