Related Experiment Videos
Persistent hypercalciuria and elevated 25-hydroxyvitamin D3 in children with infantile hypercalcaemia
E Pronicka1, E Rowińska, H Kulczycka
1Department of Metabolic Diseases, Children's Memorial Health Institute, Warsaw, Poland.
Insights
Children with a history of infantile hypercalcaemia show persistent hypercalciuria and elevated vitamin D3 metabolites, suggesting a primary metabolic defect. This condition may lead to silent nephrocalcinosis, requiring further investigation.
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.
Abstract:
The aim of the study was to characterize abnormalities of calcium-phosphate and vitamin D3 metabolism in children with a past history of "mild" Lightwood-type idiopathic infantile hypercalcaemia. Seventeen seemingly healthy children aged 2-12 years, with long-term idiopathic hypercalcaemic syndrome since infancy were studied. Two reference groups were also included (vitamin D3 intoxication/healthy and Williams groups). Despite a long-term milk-restricted diet and a restricted vitamin D3 intake, urinary calcium excretion in the study group was 0.117 +/- 0.07 mumol/kg per 24 h. Compared with the reference groups (0.047 +/- 0.029 and 0.067 +/- 0.06 mumol/kg per 24 h, P < 0.05), there was significant hypercalciuria in the children with idiopathic hypercalcaemia since infancy. Serum concentrations of 25-hydroxyvitamin D3 in the study group were also elevated compared with the reference groups (57.4 +/- 15.5 vs. 34.6 +/- 9.3 and 22.7 +/- 10.5 ng/ml). 1,25-Dihydroxyvitamin D3 levels were at the upper limit of normal (45.9 +/- 13.1 vs. 35.0 +/- 8.1 and 30.0 +/- 13.7 pg/ml). Non-progressive, clinically silent nephrocalcinosis was visible on ultrasound examinations. The disturbances of vitamin D3 and calcium-phosphate metabolism persistent in the normocalcaemic phase of idiopathic infantile hypercalcaemia may be a primary metabolic defect of the condition. The mechanisms leading to elevation of metabolites of 1,25-dihydroxy- and 25-hydroxyvitamin D3 and the relationship between this and persistent hypercalciuria and nephrocalcinosis need pathophysiological explanation.