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Bone Abstracts (2013) 1 PP5 | DOI: 10.1530/boneabs.1.PP5

1Laboratory for the Research of the Musculoskeletal System ‘Theodoros Garofalidis’, KAT Hospital, University of Athens, Athens, Greece; 2Third Orthopaedic Department, KAT Hospital, University of Athens, Athens, Greece; 3Laboratory of Human Genetics, Department of Biology, University of Athens, Athens, Greece; 4Rheumatology Department, KAT Hospital, Athens, Greece; 5Biochemistry Department, KAT Hospital, Athens, Greece.


Introduction: Autosomal dominant hypophosphatemic rickets (ADHR) is a rare form of inherited isolated renal phosphate wasting with two distinct clinical phenotypes; early-onset and late-onset. Late-onset ADHR is characterized by normal phosphate levels and growth during childhood, followed by osteomalacia with bone pain, pseudofractures and weakness in adolescence or adulthood, but with no lower extremity deformities. Most of the late-onset ADHR patients are women and pregnancy seems to be a precipitating event, while a number of patients may spontaneously resolve the phosphate wasting defect.

Case report: A 38-year-old female was referred to our department due to delayed union of a transcervical fracture of the left femur, severe hypophosphatemia, generalized bone pain and proximal muscle weakness. Past history revealed two distinct episodes of diffuse musculoskeletal pain following her pregnancies that resolved spontaneously. Family history was negative and her two children had normal phosphate levels. Radiology investigation revealed looser zones on pubic rami and right ischial ramus and diffuse osteopenia with biconcave deformation of lumbar vertebrae. Laboratory investigation revealed severe hypophosphatemia, phosphaturia, normal calcium, iPTH and 25(OH)D levels, while calcitriol levels were inappropriately normal. She was treated with phosphate salts and alphacalcidol. Six months later there was complete resolution of the symptoms, improvement of radiology abnormalities, while phosphate levels were improved. One year later, we were able to determine fibroblast growth factor–23 (FGF23) levels, which were within normal limits. Given that result, along with the significant improvement of the patient’s clinical and laboratory findings and the diminution of phosphate salt dose the possibility of late-onset ADHR was raised. Genetic analysis revealed that the patient was heterozygous for R176Q mutation of FGF23 gene, a mutation responsible for ADHR.

Conclusion: The spontaneous remission of phosphate wasting along with the normal concentrations of FGF23 led to the correct diagnosis, confirmed by the appropriate genetic testing.

Volume 1

European Calcified Tissue Society Congress 2013

Lisbon, Portugal
18 May 2013 - 22 May 2013

European Calcified Tissue Society 

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