| Title | Hypophosphatemic rickets with hypercalciuria due to mutation in SLC34A3/type IIc sodium-phosphate cotransporter: presentation as hypercalciuria and nephrolithiasis. | | Author(s) | Tencza AL, Ichikawa S, Dang A, Kenagy D, McCarthy E, Econs MJ, Levine MA | | Institution | Cleveland Clinic Lerner College of Medicine at Case Western Reserve University, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA. | | Source | J Clin Endocrinol Metab 2009 Nov; 94(11):4433-8. | | Abstract | CONTEXT: Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is a metabolic disorder due to homozygous loss-of-function mutations in the SLC34A3 gene encoding the renal type IIc sodium-phosphate cotransporter (NaPi-IIc). The typical presentation is severe rickets and hypophosphatemia, and hypercalciuria is often discovered later or overlooked.
OBJECTIVE: We sought to determine the genetic basis for severe hypercalciuria and nephrolithiasis/nephrocalcinosis in an adolescent male with elevated serum levels of calcitriol but normal serum levels of calcium and phosphorus.
DESIGN AND SETTING: We used PCR to analyze the SLC34A3 gene in the proband and members of his family.
RESULTS: The proband was a compound heterozygote for two SLC34A3 missense mutations, a novel c.544C-->T in exon 6 that results in replacement of arginine at position 182 by tryptophan (R182W) and c.575C-->T in exon 7 that results in replacement of serine at position 192 by leucine (S192L). The R182W and S192L alleles were inherited from the mother and father, respectively, both of whom had hypercalciuria. A clinically unaffected brother was heterozygous for S192L.
CONCLUSION: We report a novel mutation in the SLC34A3 gene in a patient with an unusual presentation of HHRH. This report emphasizes that moderate and severe hypercalciuria can be manifestations of heterozygous or homozygous loss-of-function mutations in the SLC34A3 gene, respectively, providing further evidence for a gene dosage effect in determining the phenotype. HHRH may be an underdiagnosed condition that can masquerade as idiopathic hypercalciuria or osteopenia. | | Language | eng | | Pub Type(s) | Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
| | PubMed ID | 19820004 |
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