Persistent hypercalciuria and elevated 25-hydroxyvitamin D3 in children with infantile hypercalcaemia

Area of Science:

• Pediatric Endocrinology
• Metabolic Disorders
• Nephrology

Background:

• Idiopathic infantile hypercalcaemia (IIH) is a rare condition.
• Mild forms of IIH may persist into childhood.
• Long-term consequences of IIH on calcium-phosphate and vitamin D3 metabolism are not fully understood.

Purpose of the Study:

• To characterize calcium-phosphate and vitamin D3 metabolism abnormalities in children with a history of mild IIH.
• To investigate persistent hypercalciuria and nephrocalcinosis in these children.

Main Methods:

• Studied 17 children (2-12 years) with a history of IIH.
• Included two reference groups: vitamin D3 intoxication and Williams syndrome.
• Measured urinary calcium excretion, serum 25-hydroxyvitamin D3, and 1,25-dihydroxyvitamin D3 levels.
• Utilized ultrasound for nephrocalcinosis detection.

Main Results:

• Children with IIH history exhibited significant hypercalciuria compared to reference groups.
• Elevated serum 25-hydroxyvitamin D3 levels were observed in the study group.
• 1,25-dihydroxyvitamin D3 levels were at the upper limit of normal.
• Clinically silent nephrocalcinosis was detected via ultrasound.

Conclusions:

• Disturbances in vitamin D3 and calcium-phosphate metabolism persist in the normocalcemic phase of IIH.
• These persistent abnormalities may represent a primary metabolic defect.
• Further research is needed to elucidate the mechanisms of elevated vitamin D3 metabolites, hypercalciuria, and nephrocalcinosis in IIH.