Novel Glial Cells Missing-2 (GCM2) variants in parathyroid disorders

Area of Science:

• Endocrinology
• Genetics
• Molecular Biology

Background:

• Familial hypoparathyroidism and familial isolated hyperparathyroidism (FIHP) are rare endocrine disorders.
• The glial cells missing-2 (GCM2) gene encodes a crucial transcription factor for parathyroid gland development and function.

Purpose of the Study:

• To investigate GCM2 gene variants in familial hypoparathyroidism and FIHP.
• To elucidate the functional consequences of identified GCM2 variants on transcriptional activity and DNA binding.

Main Methods:

• Genetic sequencing (Sanger and other methods) of GCM2 and related genes in affected families.
• In vitro functional analyses, including luciferase assays, oligonucleotide pull-down assays, and in silico structural modeling.

Main Results:

• A novel homozygous GCM2 mutation (p.R67C) causing loss of DNA binding and transcriptional activity was identified in hypoparathyroidism.
• Novel heterozygous GCM2 variants (p.I383M, p.T386S) and a known variant (p.Y394S) associated with enhanced PTH promoter activity were found in FIHP.
• Activating GCM2 variants were identified in individuals with parathyroid carcinoma, suggesting a role in disease aggressiveness.

Conclusions:

• Inactivating GCM2 mutations are causative of familial hypoparathyroidism.
• Activating GCM2 variants are associated with FIHP and may contribute to parathyroid tumorigenesis.
• GCM2 variants play a significant role in the pathogenesis of parathyroid disorders.