Persistent hypercalciuria and elevated 25-hydroxyvitamin D3 in children with infantile hypercalcaemia.
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.
Pronicka
E
E
Department of Metabolic Diseases, Children's Memorial Health Institute, Warsaw, Poland.
Rowińska
E
E
Kulczycka
H
H
Lukaszkiewicz
J
J
Lorenc
R
R
Janas
R
R
D000293:Adolescent; D002112:Calcifediol / Q000652:urine*; D002116:Calcitonin / Q000097:blood; D002118:Calcium / Q000097:blood / Q000378:metabolism; D002128:Calcium Metabolism Disorders / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000652:urine*; D007223:Infant; D007677:Kidney Function Tests; D008297:Male; D009397:Nephrocalcinosis / Q000652:urine; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood / Q000378:metabolism
D010281:Parathyroid Hormone; D010758:Phosphorus; D002116:Calcitonin; D002112:Calcifediol; D002118:Calcium