New Concepts About Familial Isolated Hyperparathyroidism.

Area of Science:

• Endocrinology
• Genetics
• Oncology

Background:

• Familial isolated hyperparathyroidism (FIHP) is primary hyperparathyroidism (FH) without other syndrome features.
• FIHP is difficult to study due to small family groups and mild symptoms.

Purpose of the Study:

• To explore new concepts of FIHP within its definition.
• To identify genetic mutations associated with FIHP.
• To characterize clinical and mutational components of FIHP.

Main Methods:

• PubMed searches for FIHP, FH syndromes, and associated gene mutations.
• Analysis of clinical and mutational data from FIHP kindreds.

Main Results:

• FIHP can involve incomplete forms of MEN1, familial hypocalciuric hypercalcemia, or HJT syndromes.
• 17% of FIHP kindreds studied had germline activating GCM2 mutations.
• FIHP kindreds, with or without GCM2 mutations, typically involve only two primary hyperparathyroidism cases, possibly due to low screening rates.

Conclusions:

• Current FIHP concepts focus on kindreds without MEN1, CASR, or CDC73 mutations.
• Germline activating GCM2 mutations were identified in 17% of FIHP kindreds.
• More research is needed to determine unique clinical features of FIHP, with or without GCM2 mutations.