Unusual case of neonatal hypercalcemia

Area of Science:

• Endocrinology
• Genetics
• Neonatal Medicine

Background:

• Neonatal hyperparathyroidism is a rare condition characterized by elevated parathyroid hormone levels in newborns.
• Calcium sensing receptor (CASR) mutations are known to affect calcium homeostasis.
• Inactivating CASR mutations lead to hypercalcemia, while activating mutations cause hypocalcemia.

Observation:

• A rare case of neonatal severe hyperparathyroidism was diagnosed.
• The condition was secondary to a homozygous inactivating mutation in the calcium sensing receptor (CASR).
• Genetics team diagnosed the mutation.

Findings:

• Homozygous inactivating CASR mutations result in severe neonatal hyperparathyroidism.
• Heterozygous CASR mutations typically cause milder, asymptomatic hypercalcemia.
• The identified mutation underscores the critical role of CASR in regulating calcium levels from birth.

Implications:

• This case highlights the importance of genetic testing in diagnosing neonatal hypercalcemia.
• Understanding CASR mutations is crucial for managing severe neonatal hyperparathyroidism.
• Early diagnosis and management can improve outcomes for affected infants.