A retrospective study of the clinical, biochemical and radiological profile of children with genetic hypophosphataemic rickets: Response to conventional treatment
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Abstract
Background. In South Africa, there is a paucity of data on the profile of hypophosphataemic rickets and response to conventional treatment like oral phosphate and alfacalcidol
Objectives. To assess the clinical, biochemical and radiological profile of children with genetic hypophosphataemic rickets and their response to conventional treatment.
Methods. Retrospective descriptive study of children under the age of 18 years with hypophosphataemic rickets. Height, calcium, phosphorus, alkaline phosphatase (ALP), and parathyroid hormone (PTH) levels were assessed at 3, 6, 9 and 12 months of age and annually thereafter. The Thacher radiological score at baseline and at regular intervals was determined after commencing treatment.
Results. Seventy patients met the inclusion criteria. A positive family history was obtained in 32 (46%) patients. Thirty-three (47%) patients were poorly compliant with treatment. The patients were short-statured with a mean height-for-age Z-score (HAZ) of –3.4 (1.79). The mean (standard deviation) calcium, phosphate, ALP and PTH levels and median (range) Thacher score were 2.3 (0.16) mmol/L, 0.84 (0.19) mmol/L, 776.6 (531) U/L, 7.15 (4.8) pmol/L and 8 (4 - 8), respectively, at baseline. At 5-year follow-up, improvements were seen in ALP (525 (232) v. 776 (531); p<0.001) and Thacher scores (2 (1-3.5) v. 8 (4 - 8); p=0.01) with treatment, however, there were no changes in phosphate levels or HAZ.
Conclusion. Conventional therapy for treatment of hypophosphataemic rickets is not associated with an improvement in HAZ despite an improvement of the Thacher score and ALP. Compliance is a major challenge for majority of patients.
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