Elsevier

The Journal of Pediatrics

Volume 163, Issue 4, October 2013, Pages 1208-1210
The Journal of Pediatrics

Clinical and Laboratory Observation
Lightwood Syndrome Revisited with a Novel Mutation in CYP24 and Vitamin D Supplement Recommendations

https://doi.org/10.1016/j.jpeds.2013.04.056Get rights and content

A novel mutation in CYP24A1 provides insight into idiopathic infantile hypercalcemia. In this report of 3 brothers, in twins supplemented with vitamin D (1900 IU/d), only the twin homozygous for CYP24A1 exhibited idiopathic infantile hypercalcemia. A subsequently affected younger brother given vitamin D 400 IU/d was not hypercalcemic.

Section snippets

Case Report

The index case, one of the twins, was born at 36 weeks gestation and treated with vitamin D (400 IU from fortified milk formula + 1500 IU supplementation because of prematurity). He presented at 6 months of age with vomiting and failure to thrive. He had severe hypercalcemia (3.68 mmol/L, normal value < 2.6) with low serum level PTH at 1 ng/L (normal value 10-55), slightly elevated serum level 25 (OH) D at 140 nmol/L, normal serum level of 1,25(OH)2D at 96 pmol/L (normal value 60-120), and

Discussion

This case illustrates the genotype/phenotype correlation with the CYP24A1 mutation together with a variable response to the dose of vitamin D supplementation. In the twins who received the same high vitamin D supplementation, it was only the child homozygous for the mutation who exhibited hypercalcemia, hypercalciuria, and resulting nephrocalcinosis (IIH). Conversely, in the 2 brothers with the same mutation, it was only the child who received high vitamin D supplementation who developed IIH.

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The authors declare no conflicts of interest.

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