Primary hyperparathyroidism in infancy associated with familial hypocalciuric hypercalcemia

Area of Science:

• Endocrinology
• Genetics
• Pediatrics

Background:

• Primary hyperparathyroidism (HPT) in infancy is rare and presents with severe symptoms.
• Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disorder characterized by hypercalcemia and low urinary calcium excretion.

Observation:

• A case of primary HPT in an infant with hypotonia and feeding difficulties is presented.
• The infant's maternal family members exhibited asymptomatic hypercalcemia consistent with FHH.
• Genetic analysis revealed a familial pattern of FHH in the maternal lineage.

Findings:

• The infant's primary HPT resolved after parathyroidectomy, but biochemical findings consistent with FHH persisted.
• Clinically healthy relatives demonstrated hypercalcemia with normal parathyroid hormone levels and low urinary calcium excretion.
• The study suggests autosomal dominant inheritance of FHH, with variable clinical penetrance.

Implications:

• FHH can manifest as either asymptomatic hypercalcemia or symptomatic primary HPT in affected infants.
• Early diagnosis and genetic counseling are crucial for families with a history of FHH.
• Understanding the genetic basis of FHH is essential for managing hypercalcemic disorders in pediatric populations.