The Effect of Growth Hormone Treatment on Biochemical Indices in Hypophosphatemic Rickets

Darendelıler, Feyza; Baş, Firdevs; Karaaslan, N.; Hekim, Nezih; Bundak, Rüveyde; Saka, Nurçin; Günöz, Hülya

doi:10.1159/000049994

Cited by 2 publications

(1 citation statement)

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“…The results have varied in terms of reestablishment of phosphorus homeostasis and the achievement of a better growth performance (62)(63)(64)(65). In two studies improvement in growth was noticed but with increased disproportion between upper and lower segments, predominating the trunk growth (66,67).…”

Section: Treatmentmentioning

confidence: 99%

Hypophosphatemic rickets and osteomalacia

Filho

Castro²,

Damiani

2006

Arq Bras Endocrinol Metab

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The hypophosphatemic conditions that interfere in bone mineralization comprise many hereditary or acquired diseases, all of them sharing the same pathophysiologic mechanism: reduction in the phosphate reabsorption by the renal tubuli. This process leads to chronic hyperphosphaturia and hypophosphatemia, associated with inappropriately normal or low levels of calcitriol, causing osteomalacia or rickets in children and osteomalacia in adults. X-linked hypophosphatemic rickets, autosomaldominant hypophosphatemic rickets, and tumor-induced osteomalacia are the main syndromes involved in the hypophosphatemic rickets. Although these conditions exhibit different etiologies, there is a common link among them: increased activity of a phosphaturic factor, being the fibroblast growth factor 23 (FGF-23) the most studied one and to which is attributed a central role in the pathophysiology of the hyperphosphaturic disturbances. Activating mutations of FGF-23 and inactivating mutations in the PHEX gene (a gene on the X chromosome that codes for a Zn-metaloendopeptidase proteolytic enzyme which regulates the phosphate) involved in the regulation of FGF-23 have been identified and have been implicated in the pathogenesis of these disturbances. Genetic studies tend to show that the phosphorus homeostasis depends on a complex osteo-renal metabolic axis, whose mechanisms of interaction have been poorly understood so far. This paper reviews the current knowledge status concerning the pathophysiology of phosphate metabolism regulation and the pathophysiologic basis of hypophosphatemic rickets. It also analyzes the clinical picture and the therapeutic aspects of these conditions as well. RESUMORaquitismo Hipofosfatêmico e Osteomalácia. Os distúrbios hipofosfatêmicos que comprometem a mineralização óssea englobam várias doenças, hereditárias e adquiridas, as quais compartilham um mesmo mecanismo fisiopatológico: a diminuição da reabsorção de fosfato nos túbulos renais. Este processo promove hiperfosfatúria e hipofosfatemia crônicas, associadas a níveis inapropriadamente normais ou baixos de 1,25 (OH) 2 D 3 , com conseqüente desordem do metabolismo ósteo-mineral, resultando em raquitismo e osteomalá-cia na faixa etária pediátrica e em osteomalácia nos adultos. O raquitismo hipofosfatêmico ligado ao X, o raquitismo hipofosfatêmico autossômico dominante e a osteomalácia induzida por tumor são as principais síndromes que constituem os raquitismos hipofosfatêmicos. Apesar de estas doenças apresentarem etiopatogenias distintas, as evidências bioquímico-moleculares indicam uma base fisiopatológica em comum: maior atividade de um agente fosfatúrico, sendo o fator de crescimento do fibroblasto 23 (FGF-23) o mais estudado e ao qual é atribuído um papel central na fisiopatologia destes distúrbios. Várias mutações ativadoras do gene do FGF-23 e mutações inativadoras do

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