Ann Pediatr Endocrinol Metab.  2019 Mar;24(1):64-67. 10.6065/apem.2019.24.1.64.

Infantile hypercalcemia with novel compound heterozygous mutation in SLC34A1 encoding renal sodium-phosphate cotransporter 2a: a case report

• Kang SJ
• Lee R
• Kim HS

• KMID: 2447379
• DOI: http://doi.org/10.6065/apem.2019.24.1.64

Abstract

Idiopathic infantile hypercalcemia is characterized by hypercalcemia, dehydration, vomiting, and failure to thrive, and it is due to mutations in 24-hydroxylase (CYP24A1). Recently, mutations in sodium-phosphate cotransporter (SLC34A1) expressed in the kidney were discovered as an additional cause of idiopathic infantile hypercalcemia. This report describes a female infant admitted for evaluation of nephrocalcinosis. She presented with hypercalcemia, hypercalciuria, low intact parathyroid hormone level, and high 1,25-dihydroxyvitamin D3 level. Exome sequencing identified novel compound heterozygous mutations in SLC34A1 (c.1337G>A, c.1483C>T). The patient was treated with fluids for hydration, furosemide, a corticosteroid, and restriction of calcium/vitamin D intake. At the age of 7 months, the patient's calcium level was within the normal range, and hypercalciuria waxed and waned. Renal echogenicity improved on the follow-up ultrasonogram, and developmental delay was not noted. In cases of hypercalcemia with subsequent hypercalciuria, DNA analysis for SLC34A1 gene mutations and CYP24A1 gene mutations should be performed. Further studies are required to obtain long-term data on hypercalciuria and nephrocalcinosis.

Keyword

Hypercalcemia; Hypercalciuria; Hypophosphatemia; Vitamin D

MeSH Terms

Calcitriol
Calcium
Dehydration
DNA
Exome
Failure to Thrive
Female
Follow-Up Studies
Furosemide
Humans
Hypercalcemia*
Hypercalciuria
Hypophosphatemia
Infant
Kidney
Nephrocalcinosis
Parathyroid Hormone
Reference Values
Sodium-Phosphate Cotransporter Proteins*
Ultrasonography
Vitamin D
Vitamin D3 24-Hydroxylase
Vomiting
Calcitriol
Calcium
DNA
Furosemide
Parathyroid Hormone
Sodium-Phosphate Cotransporter Proteins
Vitamin D
Vitamin D3 24-Hydroxylase

Figure

• 

  Fig. 1. (A) Medullary nephrocalcinosis of the left kidney on renal ultrasonography in the patient at admission. (B) Improved medullary nephrocalcinosis of the left kidney on the follow-up renal ultrasonography after 3 months.

• 

  Fig. 2. Sanger sequencing confirmation of compound heterozygous mutations of SLC34A1. (A) Heterozygous mutation of c.1337G > A in exon 12 of the SLC34A1 gene. (B) Heterozygous mutation of c.1483C > T in exon 13 of the SLC34A1 gene.

• 

  Fig. 3. Changes of serum calcium, phosphate, and urinary calcium/creatinine (Ca/Cr) ratio.

Reference

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