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Updated: Oct 14, 2026
Metabolic Labeling of Leucine Rich Repeat Kinases 1 and 2 with Radioactive Phosphate
Published on: September 18, 2013
Laboratory-based case finding using phosphate and alkaline phosphatase to identify genetic and nutritional rickets in
Beatriz Domínguez-Sevillano1,2, Mary Alejandra Ferrín-Ferrín1, David Cembrero-Fuciños3
1Servicio de Pediatría, Hospital Universitario de Salamanca, Salamanca, Spain.
Introduction:
Hypophosphatemic rickets is a rare disease characterized by renal phosphate loss, leading to chronic hypophosphatemia, elevated alkaline phosphatase, and skeletal symptoms that may remain unnoticed until advanced stages. Early diagnosis is essential because effective treatment is available to reduce complications.
Objectives:
To evaluate a laboratory-based case-finding strategy for identifying oligosymptomatic patients with hypophosphatemic rickets using phosphorus and alkaline phosphatase results in a pediatric population.
Methods:
A descriptive observational study was conducted in patients under 18 years of age at a tertiary care hospital between June 2021 and July 2025. Of 47,127 phosphorus or alkaline phosphatase measurements requested, 45,923 measurements corresponding to 28,045 tests from 12,513 patients were analyzed after exclusions. Test showing hypophosphatemia and/or elevated alkaline phosphatase were identified, and X-rays and clinical data were reviewed for classification.
Results:
A total of 22,860 phosphorus measurements and 23,063 alkaline phosphatase measurements were analyzed, with both parameters available in 17,878 laboratory tests. Hypophosphatemia was observed in 2,281 phosphorus measurements (9.98%), and elevated alkaline phosphatase in 3,301 measurements (14.3%). Fifty-five laboratory tests (0.31%) from 37 patients simultaneously met the criteria for hypophosphatemia (<-2 SD) and elevated alkaline phosphatase (>+2 SD); 56.8% were male, with a mean age of 6.5 ± 6.0 years. Following clinical review, 15 patients (40.5%) were classified as having a bone mineral metabolism disorder, including 10 with osteopenia of prematurity, three with nutritional rickets, one with a pathogenic variant in PHEX, and one with osteoporosis in the context of ReNU syndrome; 10 patients (27.0%) were classified in the acute/critical illness group and 12 (32.4%) in the other category. Radiographs were available in 30 patients, with findings consistent with rickets in three (10%). One previously unrecognized case of mild nutritional rickets was identified.
Conclusions:
Laboratory-based case finding using phosphorus and alkaline phosphatase may help identify pediatric bone metabolism disorders, including forms of rickets. Combined hypophosphatemia and elevated alkaline phosphatase may be useful for guiding etiological investigation. This approach may complement clinical evaluation and facilitate earlier diagnosis. Early identification is clinically relevant because treatments can modify disease course and reduce long-term complications in children with confirmed forms of rickets, when appropriate.
