Familial X-chromosome linked hypophosphatemic rickets: Report of a case

Rabanal C.L.; Gambini J.P. · Acta Medica Peruana (2023) · DOI: 10.35663/amp.2023.401.2431

Resumen

Phosphate is regulated by the kidneys and the osseus system, mainly due to the action of parathyroid hormone (PTH) and a recently described molecule, fibroblast growth factor 23 (FGF-23). We present the cases of two patients, mother and son with X-chromosome linked hypophosphatemic rickets. The genetic study was performed, and a mutation in the PHEX gene was identified, a splicing type pathogenic variant in hemizygosis. This mutation was previously described as HGMD CS126536. Hypophosphatemic rickets belongs to a group of tubulopathies characterized by hyperphosphaturia. PHEX gene mutation with function loss leads to increased FGF-23 levels. PHEX degrades FGF-23 into inactive fragments, preventing excessive phosphate excretion and the development of hypophosphatemia. In patients with PTH or vitamin D non-dependent hypophosphatemia, a diagnosis of X-chromosome linked hypophosphatemic rickets should be considered.

Instituciones: Universidad Peruana Cayetano Heredia; Universidad Nacional Mayor de San Marcos